Twin blasts targeting Syria's army command headquarters rocked the capital on Wednesday, setting off hours of sporadic gunbattles and a raging fire inside the heavily guarded compound, state-run media and witnesses said. 
 
 In this image taken from video obtained from the Syria 2011 Archives, which has been authenticated based on its contents and other AP reporting, black smoke rises from Syria's army command headquarters... (Associated Press) 
 
 A Free Syrian Army fighter fires at Syrian Army positions during clashes in Aleppo, Syria, Tuesday, Sept. 25, 2012. Over the past few months, rebels have increasingly targeted security sites and symbols... (Associated Press) 
 
 A woman cries while holding the body of her brother, who was killed by Syrian Army, in front of Dar El Shifa hospital in Aleppo, Syria, Tuesday, Sept. 25, 2012. Over the past few months, rebels have increasingly... (Associated Press) 
 
 This photo released by the Syrian official news agency SANA, shows Syrian government forces speaking with Syrian women as they patrol the damaged area of the al-Arqoub district in Aleppo, Syria, Tuesday,... (Associated Press) 
 
 A Syrian woman cries near Dar El Shifa hospital while the body of her brother, killed by Syrian Army, lies on the street in Aleppo, Syria, Tuesday, Sept. 25, 2012. Over the past few months, rebels have... (Associated Press) 
 
 An army statement said no military commanders or personnel were hurt in the explosions, one of which was from a car bomb. But Iranian Press TV said one of its correspondents, 33-year-old Maya Nasser, a Syrian national, died in an exchange of fire in the area following the blasts. 
 
 The explosions were the latest to hit the Syrian capital as the country's civil war intensified and appeared to show the deep reach of the rebels determined to topple President Bashar Assad's regime. 
 
 Syria's state-run news agency, SANA, said the explosions struck just before 7 a.m. (0400 GMT) near the landmark Omayyad Square. They were heard several miles (kilometers) away and shattered the windows of the Dama Rose hotel and other nearby buildings. 
 
 The army command building was in flames, sending huge columns of thick black smoke that hung over Damascus for several hours following the blasts. 
 
 Witnesses said the explosions were followed by heavy gunfire that stretched on for hours at the Omayyad Square and around the military compound. One witness who managed to get close to the area, which was cordoned off, saw panicked soldiers shooting in the air randomly as they ran. 
 
 The witness, who spoke on condition of anonymity for fear of reprisals, said it appears that rebels may have been holed up inside the army command building, from where the sound of gunfire could clearly be heard. 
 
 The British-based Syrian Observatory for Human Rights, which relies on a network of activists on the ground, said heavy clashes were taking place inside the compound of the army command, adding that there were casualties on both sides. 
 
 "The explosions shook the entire apartment and the windows shattered," said a resident of the nearby Abu Rummaneh district who spoke on condition of anonymity out of security concerns. "It was like a quake." 
 
 The army statement said the blasts were caused by a car bomb and an explosive device that went off near the army command buildings. It said "terrorists" in the area simultaneously opened fire randomly to terrorize people, adding that authorities were pursuing the gunmen. Syrian authorities regularly refer to rebels fighting to topple Assad's regime as terrorists. 
 
 The statement said a number of guards were wounded. 
 
 "I can confirm that all our comrades in the military command and defense ministry are fine," Information Minister Omran Zoubi told Syrian TV, which is located near the site of the explosion, in a telephone call. 
 
 "Everything is normal," he said. "There was a terrorist act, perhaps near a significant location, yes, this is true, but they failed as usual to achieve their goals." 
 
 Ambulances were rushed to the site as police sealed off the area to traffic and journalists. Traffic in other areas snarled as checkpoints were set up, blocking access to the capital from the suburbs. 
 
 Syria's unrest began in March 2011 when protests calling for political change met a violent government crackdown. Many in the opposition have since taken up arms as the conflict morphed into a civil war that activists say has killed nearly 30,000 people. Over the past few months, the rebels have increasingly targeted security sites and symbols of regime power in a bid to turn the tide in the fighting. 
 
 On July 18, rebels penetrated the heart of Syria's power elite, detonating a bomb inside a high-level crisis meeting in Damascus that killed three top regime officials, including Assad's brother-in-law and the defense minister. Other large blasts have targeted the headquarters of security agencies in the capital, killing scores of people this year. 
 
 On Tuesday, several bombs went off inside a Damascus school that activists said was being used by regime forces as a security headquarters. Several people were wounded. 
 
 Syria's conflict was the focus of attention as world leaders gathered at the U.N. General Assembly's annual meeting in New York this week. 
 
 U.N. Secretary-General Ban Ki-moon demanded international action to stop the war in Syria, telling a somber gathering of world leaders Tuesday that the 18-month conflict had become "a regional calamity with global ramifications." 
 
 Ban, declaring that the situation in Syria is getting worse every day, called the conflict a serious and growing threat to international peace and security that requires attention from the deeply divided U.N. Security Council. 
 
 That appears highly unlikely, however, at least in the near future. 
 
 Russia and China have vetoed three Western-backed resolutions aimed at pressuring Assad to end the violence and enter negotiations on a political transition, leaving the U.N.'s most powerful body paralyzed in what some diplomats say is the worst crisis since the U.S.-Soviet standoff during the Cold War. 
 
 In sharp contrast to the U.N. chief, President Barack Obama pledged U.S. support for Syrians trying to oust Assad _ "a dictator who massacres his own people." 
 
 ___ 
 
 Karam reported from Beirut. ||||| (CBS/AP) - Syria's government said on Monday that Prime Minister Riad Hijab had been fired -- but a spokesman for the premiere and opposition members said he had actually become the latest official to defect from President Bashar Assad's autocratic regime. 
 
 State-controlled Syrian TV made the announcement Monday of Hijab's dismissal from the post, which he assumed just two months ago, without giving any further detail. 
 
 A reliable opposition source tells CBS News' Khaled Wassef that Hijab and his family have safely left Syrian territory. 
 
 Ahmad Kassim, a senior official with the Free Syrian Army, told the Associated Press that Hijab defected to Jordan along with three other ministers. The other ministers' identities were not immediately known. 
 
 A spokesman for the Jordanian Prime Minister said on Jordanian TV that Hijab had not yet entered the country. 
 
 Video: Syrian rebels anticipate large-scale assault on Aleppo 
 
 Jordan's king: "Clock is ticking" in Syria 
 
 Video: Battles rage in Syrian rebel territory 
 
 If confirmed, Hijab's would be only the latest in a series of defections of senior political and military defections from Syria. CBS News correspondent Holly Williams reports that as many as 20 Syrian generals are believed to have abandoned the regime already, with most of them believed to have joined the Free Syrian Army. 
 
 According to the Al Jazeera television network, the rebel Free Syrian Army secured the exit of Hijab and his family from Syria into neighboring Jordan. Al Jazeera quoted a spokesperson for Hijab as saying the defected premiere will "join the ranks" of the Syrian opposition. 
 
 Sorry, your browser does not support iframes 
 
 Shortly before the announcement about Hijab, a bomb ripped through the third floor of the state TV building in Damascus, shattering several offices and wounding at least three employees, Syrian TV said. 
 
 The explosion was the latest in the Syrian capital, which has seen a string of suicide attacks and other bombings in the past few months as the country's civil war has escalated and the rebels grow bolder in their tactics. The TV building, which also houses state-run radio, is located at the Umawiyyeen roundabout in central Damascus. 
 
 After Monday's blast, the TV remained on air despite what was another severe breach of a state institution and a heavily guarded area in the Syrian capital. A bomb that exploded in the state security headquarters in Damascus on July 18 killed four of Syria's top security leaders. 
 
 A pro-government private Syrian TV station, Al-Ikhbariya, broadcast images of the damage at the state TV building. The footage showed destroyed walls, overturned desks, blown-out cabinet doors, broken glass and dangling electricity cables. A few TV workers were shown tending to a wounded colleague. 
 
 Information Minister Omran al-Zoubi said the bomb blast caused heavy material damage and light injuries among the employees. 
 
 "Syrian TV was not disrupted, and we will keep up our transmission no matter how some powers do their best to silence us," Zoubi told CBS News' George Baghdadi. 
 
 He blamed Qatar, Saudi Arabia and Israel for the attack. Syrian authorities accuse the Gulf countries and Israel of supporting the rebels fighting against President Bashar Assad's troops and fueling the insurgency in Syria. 
 
 Syria's rebels have grown increasingly confident in recent months. In July, the rebels and Syrian regime forces fought intense battles for a week in Damascus in what was the opposition fighters' biggest challenge so far in the capital. 
 
 The government claimed Saturday it was now in full control of all districts in the capital, after purging one of the last rebel-held areas, but clashes have continued in some districts of Damascus. 
 
 On Saturday, gunmen snatched 48 Iranians just outside Damascus in a brazen attack. Iran said those abducted were pilgrims who were traveling on a bus taking them from the suburb of Sayeda Zeinab, about 10 miles south of Damascus, to the airport to return home when they were kidnapped. 
 
 But the Iranians' captors claimed in a video broadcast on Al-Arabiya TV station Sunday that one of the captives was an officer of Iran's powerful Revolutionary Guards and that the 48 were on a "reconnaissance mission" in the capital. 
 
 Mainly Shiite Iran is a close ally of the beleaguered Syrian government, which is dominated by the minority Alawite sect, an offshoot of Shiite Islam. ||||| Image caption Video footage taken by activists in Harasta, which could not be verified, showed a large explosion 
 
 Rebels have carried out a suicide bomb attack overnight on an intelligence agency compound in a suburb of the Syrian capital, Damascus, reports say. 
 
 The al-Nusra Front, a jihadist militant group, said explosives-filled vehicles had been blown up outside the Air Force Intelligence complex in Harasta. 
 
 Residents said there were several huge blasts, followed by fierce clashes. 
 
 One activist group said dozens of people were killed and expressed fears for the fate of the agency's prisoners. 
 
 Human rights activists say hundreds of opponents of President Bashar al-Assad have been detained and tortured by Air Force Intelligence (AFI) across the country since the uprising began in March 2011. 
 
 AFI is seen by some as the elite agency of Syria's intelligence empire. 
 
 Though smaller than Military Intelligence, in the past it has played a leading role in operations against Islamist opposition groups, as well as covert actions abroad, and has a reputation for brutality. 
 
 'Citadel of repression' 
 
 The fate of hundreds of prisoners being held in the basements of the [Air Force Intelligence complex] is still unknown Rami Abdul Rahman, Syrian Observatory for Human Rights 
 
 A statement issued by the al-Nusra Front said it had targeted the AFI "because it is one of the most notorious security divisions, and a citadel of repression whose extent is known only to God". 
 
 The group, which has claimed to be behind a series of deadly bombings since January, said a vehicle packed with nine tonnes of explosives had been driven up to the AFI compound in Harasta and blown up. 
 
 Twenty-five minutes later, another al-Nusra Front fighter blew up a one-tonne bomb hidden inside an ambulance, targeting survivors, it added. The fighters then fired mortars at the complex, the statement said. 
 
 The Syrian Observatory for Human Rights (SOHR), a UK-based activist group, reported that several large explosions had shaken homes overnight in Harasta, as well as in the nearby suburbs of Jobar and Qabun. 
 
 The blasts were followed by violent clashes in several parts of Harasta, with government forces firing heavy weapons and mortars, it added. 
 
 SOHR head Rami Abdul Rahman told the AFP news agency that dozens of people had been killed in the suicide attacks. 
 
 Image caption The al-Nusra Front has said it was behind many of the bombings that have rocked Syria this year 
 
 "The fate of hundreds of prisoners being held in the basements of the [security complex] is still unknown," he added. "The regime has not said a word about what happened last night." 
 
 The SOHR is one of the most prominent organisations documenting and reporting incidents and casualties in the Syrian conflict. The group says its reports are impartial, though its information cannot be verified. 
 
 A Syrian official told the Associated Press that a suicide bomber had detonated a car bomb near the AFI complex, while pro-government al-Ikhbariya TV reported that the blast was followed by clashes. 
 
 'Unbearable' conflict 
 
 Elsewhere on Tuesday, government forces continued to attack rebel strongholds in the central city of Homs. 
 
 State TV reported that soldiers had secured large parts of the Khalidiya district and were now "pursuing the remnants of the terrorists". 
 
 Image caption Military aircraft and artillery have been targeting the Homs district of Khalidiya 
 
 News of the violence came as UN Secretary General Ban Ki-moon urged the Syrian government to immediately declare a unilateral ceasefire, and the opposition to abide by it. 
 
 "It is unbearable for the Syrian people to continue like this," he told a joint news conference in Paris with French President Francois Hollande. 
 
 Mr Ban also called on countries to stop supplying weapons to both sides. 
 
 On Monday, the BBC found evidence that weapons intended for the Saudi military have been found at a base used by Syrian rebels. 
 
 The BBC's Ian Pannell saw crates from a Ukrainian arms manufacturer - addressed to Saudi Arabia - at a rebel camp in the city of Aleppo. 
 
 Meanwhile, Nato Secretary-General Anders Fogh Rasmussen has said the alliance has "all necessary plans in place to protect and defend Turkey if necessary", amid escalating tensions on its border with Syria. 
 
 Turkish and Syrian government forces have been exchanging artillery fire since Syrian shells killed five Turkish civilians last week.
– Damascus has been rocked by bombings for the past two days, with at least two large blasts hitting Syria's military headquarters there this morning. The Free Syrian Army claimed responsibility for the attack, said to be the largest since July explosions killed President Bashar al-Assad's brother-in-law and other key aides; the BBC reports that Assad would have been able to hear today's explosions from his palace. Gunfire broke out afterward, and Maya Nasser, a TV correspondent for the Iranian Press TV, was shot dead by sniper fire during a live broadcast, report the New York Times and Press TV. Other government facilities were hit by bombs yesterday, proving the opposition can still get past government security, but the regime is downplaying the scope of the attacks while the opposition says many of Assad's forces have been killed. In other news from Syria: UN Secretary-General Ban Ki-moon called for international action at the General Assembly yesterday, calling the conflict "a regional calamity with global ramifications," the AP reports. Click for more from the General Assembly on Syria. Clashes have also been reported near Syria's border with Israel, leading the Israel Defense Forces to issue a statement declaring that "fire from Syria leaking into Israel will not be accepted."