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13 people are killed in an explosion at a funeral of an opposition activist. "Look at this, Assad!... Look at this, you murderer!" one man screams. The blast takes place in the Damascus suburbs, which has seen months of fighting. International envoy Lakhdar Brahimi is trying to broker a cease-fire by Friday.

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It's a horror show that has played out across Syria for 19 months. Those grieving the dead are themselves targeted by gunfire or deadly blasts. That cycle of death played out again Tuesday when mourners gathered to grieve a man who dared speak out against the Syrian government. A car bomb silenced them. "Children's bodies were maimed and burnt. I saw pieces of human flesh and blood on the street," witness Ahmed Al-Muadami said. This day, mourners came to honor one of 14 men who died after his arrest by Air Force Intelligence -- a much feared security apparatus that dissidents accuse of hunting down anti-government activists. Word spread quickly Tuesday that a Damascus hospital had a collection of unidentified bodies. The families of the 14 men rushed to the scene -- only to discover the bodies of their loved ones bore signs of torture. The outrage boiled over in the Damascus suburb of Muadamiyet al-Sham, where a funeral procession for one of the men morphed into a protest against President Bashar al-Assad's government. Then came the explosion near the Al-Zaitoona mosque, which is a popular gathering site for anti-government protests. "It was a car bomb parked next to the mosque where the people were gathered. The explosion killed at least 13 people and wounded over a hundred," Al-Muadami said. "One child was extremely disfigured ... we couldn't identify him." Amateur videos reportedly from the scene show a grisly aftermath. One man carried the lifeless body of a child, his face charred black and gray. "Look at this, Assad!" the man screamed. "Is this your gift to us for the Eid? Look at this, you murderer!" The Muslim holiday of Eid al-Adha begins Friday. CNN cannot independently verify the authenticity of the videos or reports of violence, as the Syrian government has restricted access to international journalists. The Damascus suburbs have seen fierce fighting for months. Opposition activists say the government has committed massacres, while the government says it is fighting armed terrorists. International envoy Lakhdar Brahimi is trying to broker a cease-fire by Friday. But the odds seem daunting. On Tuesday alone, at least 100 people were killed in Damascus and its suburbs; 50 were from Muadamiyet al-Sham, the opposition Local Coordination Committees of Syria said. The activist network said residents in the town called for blood donors after the explosion.