Ambassadors to the United Nations said on Monday that there is no doubt that Syrian President Bashar Al-Assad’s regime is behind the chemical attack near Damascus on August 21. The comments were made after the envoys were shown the report by UN investigators, who said they had found “convincing evidence” that sarin gas was used in the attack. Investigator Ake Sellstrom handed the report to UN Secretary-General Ban Ki-Moon. While the report has yet to be officially released, a photograph of the transfer of the document showed its first page. The text that could be seen noted that “environmental, chemical and medical samples” collected at the scene of the attack “provide clear and convincing evidence that surface-to-surface rockets containing the nerve gas sarin were used” in the assault in the Ghouta area. After viewing the report, Mark Lyall Grant, Britain's ambassador to the UN, said Monday there is "no remaining doubt" that the Assad regime was responsible for the chemical weapons attack. "Only the regime could have carried out this attack," said U.S. Ambassador Samantha Power, agreeing with Grant. The UN weapons report has been distributed to all 193 member states of the General Assembly, including the 15 members of the Security Council, according to CBS News . The report did not apportion blame for the attack, as UN investigators warned that it would not. As the interpretation of the evidence emerges, diplomats at the UN told CBS the report already appears to be shifting the thinking about whether a use-of-force clause should be included in the UN resolution being negotiated this week in New York based on the groundbreaking framework agreement announced Saturday by Russia and the U.S. to identify Syria's chemical weapons, place them under control of the international community. With the evidence of the report in hand, diplomats from the U.S., UK and France now say that accountability needs to be a part of the UN action -- either in the form of an International Criminal Court referral in the resolution, or as part of an international conference which UN and Arab League envoy Lakhdar Brahimi is negotiating. U.S. Secretary of State John Kerry, who paid a whirlwind visit to Jerusalem on Sunday for talks with Israeli Prime Minister Binyamin Netanyahu, warned Syria that it was not off the hook yet, despite the deal with Russia. "The threat of force remains, the threat is real," Kerry said at a joint news conference with the Israeli prime minister.