U.N. confirms use of chemical weapons in Syria The United Nations releases a much-anticipated report It finds "convincing evidence" that such weapons were used against children The report does not say who is responsible for the attacks (CNN) -- In a much-anticipated report, the United Nations has concluded that chemical weapons have been used in the Syrian conflict. Experts investigated seven instances of alleged use and found that chemical weapons were either used, or likely used, in five of those instances. The case that was most clear to inspectors was an August incident near the capital, Damascus. "The United Nations Mission collected clear and convincing evidence that chemical weapons were used also against civilians, including children, on a relatively large scale in the Ghouta area of Damascus on 21 August 2013," read the 82-page report, which was released on Thursday. Blood and urine samples from patients there tested positive for sarin and sarin signatures, it found. Anti-government activist groups say more than 1,300 people were killed in the attack in Ghouta -- many of them women and children. Graphic video footage showed rows of bodies without apparent injury, as well as people suffering convulsions or apparently struggling to breathe. U.N. inspectors also said they collected credible information, or evidence consistent with the probable use of chemical weapons, in Khan al Asal, Jobar, Saraqueb and Ashrafiah Sahnaya. They were unable to corroborate the allegation that chemical weapons were used in either Bahhariyeh or Sheik Maqsood. The report did not specify whether the government or opposition groups were responsible for the alleged attacks, which happened between March and August this year. The United Nations estimates that more than 100,000 people overall have died since the Syrian conflict began in March 2011. It began with a government crackdown on peaceful protesters during the Arab Spring movement, then slowly spiraled into a bloody, full-blown civil war. Rebel leader denies he fled Also Thursday, a top Syrian rebel commander denied that he had abandoned his post and said he is working to resolve fighting among opposition groups in the country's north. Infighting is growing And that's why I can understand the, let me say, freezing the support for a period of time," Idriss said.