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In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.

WASHINGTON The United States on Thursday carried out an air strike in Syria targeting the Islamic State militant known as "Jihadi John," who participated in gruesome videos showing the killings of American and British hostages, officials said. 
  
 One U.S. official, speaking on condition of anonymity, said the strike likely killed Mohammed Emwazi, a British citizen, but cautioned that it was too soon to make any determination. 
  
 The Pentagon said it was still assessing the effectiveness of the strike in the Syrian city of Raqqa, the de facto capital of Islamic State. 
  
 If his death is confirmed, it would be an important milestone in the U.S.-led campaign against the group and would come more than a year after U.S. President Barack Obama promised justice after the deaths of American hostages. 
  
 Dressed entirely in black, a balaclava covering all but his eyes and the bridge of his nose, "Jihadi John" became a menacing symbol of Islamic State brutality and one of the world's most wanted men. 
  
 Emwazi participated in videos showing the killings of U.S. journalists James Foley and Steven Sotloff, U.S. aid worker Peter Kassig, British aid workers David Haines and Alan Henning, Japanese journalist Kenji Goto, and other hostages. 
  
 Kassig, from Indiana, was also known as Abdul-Rahman, a name he took after converting to Islam in captivity. 
  
 Emwazi used the videos to threaten the West, admonish its Arab allies and taunt Obama and British Prime Minister David Cameron in front of petrified hostages cowering in orange jump suits. 
  
 "We are assessing the results of tonight's operation and will provide additional information as and where appropriate," said Pentagon spokesman Peter Cook. 
  
 It was not immediately clear how long it might take for a final determination. 
  
 The first U.S. official said the operation itself had been in the works for days. Still, key details remained unclear, including how the United States tracked Emwazi down and how it planned the operation. 
  
 The strike came just as the United States seeks to increase pressure on Islamic State fighters, who have seized parts of Syria and Iraq, and who Obama has vowed to defeat. 
  
 The pressure includes U.S. plans to deploy dozens of special operations forces to Syria, deliver more weaponry to U.S.-backed Syrian fighters and to thicken U.S. air strikes against the militant group. 
  
 (Reporting by Phil Stewart; Editing by Clarence Fernandez, Robert Birsel) ||||| WASHINGTON (AP) — A U.S. drone strike targeted a vehicle in Syria believed to be transporting the masked Islamic State militant known as "Jihadi John" on Thursday, according to American officials. Whether the strike killed the British man who appears in several videos depicting the beheadings of Western hostages was not known, officials said. 
  
 Mohammed Emwazi was the target of an airstrike in Raqqa, Pentagon press secretary Peter Cook said in a statement. Officials were assessing the results of the strike, he said. 
  
 A U.S. official told The Associated Press that a drone had targeted a vehicle in which Emwazi was believed to be traveling. The official was not authorized to speak publicly and requested anonymity. 
  
 Emwazi, believed to be in his mid-20s, has been described by a former hostage as a bloodthirsty psychopath who enjoyed threatening Western hostages. Spanish journalist Javier Espinosa, who had been held in Syria for more than six months after his abduction in September 2013, said Emwazi would explain precisely how the militants would carry out a beheading. 
  
 Among those beheaded by Islamic State militants in videos posted online since August 2014 were U.S. journalists Steven Sotloff and James Foley, U.S. aid worker Abdul-Rahman Kassig, British aid workers David Haines and Alan Henning, and Japanese journalist Kenji Goto. 
  
 In the videos, a tall masked figure clad in black and speaking in a British accent typically began one of the gruesome videos with a political rant and a kneeling hostage before him, then ended it holding an oversize knife in his hand with the headless victim lying before him in the sand. 
  
 Emwazi was identified as "Jihadi John" last February, although a lawyer who once represented Emwazi's father told reporters that there was no evidence supporting the accusation. Experts and others later confirmed the identification. 
  
 Emwazi was born in Kuwait and spent part of his childhood in the poor Taima area of Jahra before moving to Britain while still a boy, according to news reports quoting Syrian activists who knew the family. He attended state schools in London, then studied computer science at the University of Westminster before leaving for Syria in 2013. The woman who had been the principal at London's Quintin Kynaston Academy told the BBC earlier this year that Emwazi had been quiet and "reasonably hard-working." 
  
 Officials said Britain's intelligence community had Emwazi on its list of potential terror suspects for years but was unable to prevent him from traveling to Syria. He had been known to the nation's intelligence services since at least 2009, when he was connected with investigations into terrorism in Somalia. ||||| Story highlights U.S. forces targeted "Jihadi John" in an airstrike in Raqqa, Syria, the Pentagon announced Thursday night 
  
 It was not immediately clear whether the strike was successful 
  
 Washington (CNN) U.S. forces targeted "Jihadi John," the man who has emerged as the masked face of ISIS, in an airstrike in Raqqa, Syria, the Pentagon announced Thursday night. 
  
 "Jihadi John," whom Western officials have identified as Mohammed Emwazi, has appeared in a series of brutal execution videos, taunting Western leaders in a British accent. 
  
 It was not immediately clear whether the strike was successful. But a senior U.S. official said authorities are confident that the strike killed Emwazi, adding that the U.S. announced the strike because of Emwazi's notoriety. 
  
 This was a mission of "persistent surveillance," the official said, adding that authorities knew it was Emwazi when they took the shot. 
  
 Another U.S. official told CNN that Emwazi was in a vehicle at the time of the strike, which was launched from a drone. ||||| The British and US military worked “hand in glove” to launch an airstrike against notorious Islamic State extremist Mohammed Emwazi, the UK government has confirmed, with sources adding that there was a “high degree of certainty” he was killed in the attack. 
  
 The Pentagon confirmed late on Thursday night that US forces carried out an airstrike in Syria targeting Emwazi, the British-born Isis terrorist known as “Jihadi John” after appearing in gruesome propaganda videos depicting the beheadings of eight hostages. 
  
 Who is Mohammed Emwazi? From 'lovely boy' to Islamic State killer Read more 
  
 David Cameron made a statement from Downing Street on Friday morning confirming the attack amid reports that US officials were “99% certain” that Emwazi had been killed in a drone strike. 
  
 The prime minister said it had not been confirmed that Emwazi was dead, but described the strike as “an act of self-defence” that struck at the heart of Islamic State. Cameron added that Britain had been working “hand in glove, round the clock” with the US to track down and target Emwazi. 
  
 He said Emwazi was a threat to innocent people around the world, adding: “This was an act of self-defence. It was the right thing to do.” 
  
 Downing Street and Ministry of Defence sources were marginally less categorical in their response to the reports of his death than US sources, but added there was a “high degree of certainty that he has been killed”. 
  
 Announcing details of the strike late on Thursday night, the Pentagon press secretary, Peter Cook, said: “US forces conducted an airstrike in Raqqa, Syria, on 12 November 2015 targeting Mohamed Emwazi, also known as Jihadi John. 
  
 “Emwazi, a British citizen, participated in the videos showing the murders of US journalists Steven Sotloff and James Foley, American aid worker Abdul-Rahman [Peter] Kassig, British aid workers David Haines and Alan Henning, Japanese journalist Kenji Goto, and a number of other hostages. 
  
 “We are assessing the results of tonight’s operation and will provide additional information as and where appropriate.” 
  
 Facebook Twitter Pinterest Masked man believed to be Mohammed Emwazi in a frame from an Islamic State video. Photograph: Uncredited/AP 
  
 Jeremy Corbyn, leader of the Labour party, said it would have been preferable for Emwazi to have faced justice in a court of law. “It appears Mohammed Emwazi has been held to account for his callous and brutal crimes. However, it would have been far better for us all if he had been held to account in a court of law. These events only underline the necessity of accelerating international efforts, under the auspices of the UN, to bring an end to the Syrian conflict as part of a comprehensive regional settlement.” 
  
 The Associated Press quoted an unnamed US official saying that a drone had targeted a vehicle believed to be carrying Emwazi in Raqqa, the de facto capital of Isis in northern Syria. Fox News said a senior US military source said it was “99% sure we got him”. 
  
  
  
 Activist groups in Raqqa reported airstrikes and an explosion during the night of 12 November. A US military statement said one of eight strikes in Syria on Thursday had struck an Isis tactical unit. 
  
 Japan’s chief cabinet secretary, Yoshihide Suga, added that Tokyo was liaising with Washington over the outcome of the airstrikes. 
  
 Suga said the Japanese government was “aware of the Pentagon’s press statement on this matter, and we understand that the Pentagon is assessing the results of the operation. The government of Japan is in contact with the US government about the details.” 
  
  
  
 Emwazi is believed to have beheaded two Japanese hostages, journalist Kenji Goto and security consultant Haruna Yukawa, earlier this year. 
  
  
  
 In late January, Islamic State released a video, called A Message to the Government of Japan, showing a militant who looks and sounds like Emwazi. The man, armed with a knife and dressed in black with his face covered, stands behind Goto before beheading him. 
  
  
  
 Isis had targeted Japanese citizens after the prime minister, Shinzo Abe, publicly pledged $200m (£131m) in non-military aid to countries engaged in the fight against the group. 
  
 The family of Alan Henning, the British hostage killed by Islamic State in October 2014, was informed of the strike against Emwazi by Foreign Office officials. Henning, an aid worker from Salford, was murdered and his death was recorded in a video fronted by Emwazi. 
  
 Support is also being provided to Henning’s family by liaison officers from Greater Manchester police. 
  
 Diane Foley, the mother of James Foley, told ABC News that should Emwazi have been killed in the strike, it would be “really a small solace to us”. 
  
 “This huge effort to go after this deranged man filled with hate when they can’t make half that effort to save the hostages while these young Americans were still alive,” she said. 
  
 CNN reported that the families of Emwazi’s American victims had been informed of the strike. 
  
 Emwazi was born in Kuwait in 1988 and came to the UK in 1994 when he was six years old. His parents reported him missing in August 2013 and were reportedly told by police, four months later, that he was in Syria. 
  
 Mohammed Emwazi: from west London to Syria. 
  
 In August 2014, he made his first appearance – with his face covered – in the Islamic State video showing the beheading of Foley. In the following months he featured in similar propaganda films showing the killings of Sotloff, Haines and Henning. 
  
 In November 2014, Emwazi was believed to have carried out the killing of a Syrian military officer. He was filmed standing over the severed head of Kassig, and two months later appeared in a video killing Goto. 
  
 His nickname “Jihadi John” was given to him by a group of hostages, who described him as part of an Isis cell they named “the Beatles” because of their British accents. In February 2015, his identity was confirmed as Emwazi. 
  
 Spanish journalist Javier Espinosa, who was freed in March 2014 after six months being held hostage by Isis in Syria, later wrote in El Mundo of his experiences at Emwazi’s hands. 
  
 “Jihadi John wanted maximum drama. He had brought along an antique sword of the kind Muslim armies used in the middle ages. It was a blade of almost a metre in length with a silver handle.” 
  
 Espinosa said the Isis militant would describe in graphic detail how he would behead his hostages and carried out mock executions with a Glock pistol. |||||
Output:
After more than a year of US anti-ISIS airstrikes, "Jihadi John" might finally be history. The Pentagon says Mohammed Emwazi, the brutal militant known for decapitating Western hostages, was the target of a drone strike Thursday night near the ISIS stronghold of Raqqa in Syria, reports Reuters. Whether the strike on a vehicle actually killed the 27-year-old Briton is uncertain, and will remain so until the intelligence can be assessed. Outlets including CNN and the Guardian quote sources who are confident that the strike killed the militant, who had been under "persistent surveillance." Still, "we cannot yet be certain," British Prime Minister David Cameron told reporters Friday morning. Cameron called the mission an "act of self-defense" and "a strike at the heart" of ISIS, and he said the UK had been working closely with the US to track down the militant. Emwazi was born in Kuwait but was a naturalized British citizen, and the New York Times notes that the idea of going after him troubled rights advocates—similar to the criticism over the US decision to kill American citizen Anwar al-Awlaki. Last year, Emwazi grabbed the world's attention with gruesome videos showing the beheading of Western hostages, including three Americans. Former ISIS hostages have described him as a sadist who was fond of torturing and taunting the group's Western prisoners, the AP reports. He got the "Jihadi John" name as part of a British-accented group of militants that prisoners nicknamed the "Beatles."