A U.N. chemical weapons expert, wearing a gas mask, holds a plastic bag containing samples from one of the sites of an alleged chemical weapons attack in the Ain Tarma neighbourhood of Damascus August 29, 2013.
A report by U.N. chemical weapons experts will likely confirm that poison gas was used in an August 21 attack on Damascus suburbs that killed hundreds of people, U.N. Secretary-General Ban Ki-moon said on Friday.
"I believe that the report will be an overwhelming, overwhelming report that chemical weapons (were) used, even though I cannot publicly say at this time before I receive this report," Ban said at a U.N. meeting.
He was referring to an eagerly awaited report by the U.N. expert team led by Ake Sellstrom of Sweden.
U.N. spokesman Farhan Haq said that Ban does not have Sellstrom's report yet. Ban has said previously, however, that he was in contact with Sellstrom and had urged him to expedite his conclusions.
France's U.N. ambassador, Gerard Araud, told reporters Monday is the tentative date for Ban to present Sellstrom's report to the Security Council and other U.N. member states.
Ban also said on Friday that Syrian President Bashar al-Assad "has committed many crimes against humanity," though he did not say whether it was Assad's forces or rebels who used the chemical weapons in the August 21 attack.
While Sellstrom's report will not explicitly pin the blame on either side, diplomats say the facts they gathered could suggest which side in the 2-1/2 year civil war was responsible.
The United States and other Western powers blame forces loyal to Assad for the attack. Russian President Vladimir Putin asserts there is "every reason to believe" it was carried out by rebels.
Two Western diplomats said they strongly expect Sellstrom's report will confirm the U.S. view that sarin gas was used in the attack, which the United States says killed over 1,400 people, many of them children.
The diplomats added they expected the report would indirectly implicate the Syrian government. They declined to elaborate, but the details that the report could include are types of weapons used and trajectories.
Sellstrom's report could become a bargaining chip in talks between Russia and Western powers on conditions for Syria to give up its chemical weapons and the terms of a U.N. Security Council resolution on the matter.
President Obama said on Friday that he hopes talks on a plan to destroy Syria's chemical weapons are successful, but said that he will insist any deal is "verifiable and enforceable."
Obama made his comments after meeting in the Oval Office of the White House with Kuwait's emir, Sheikh Sabah al-Ahmad al-Jaber al-Sabah.
"I shared with the emir my hope that the negotiations that are currently taking place between Secretary of State Kerry and Foreign Minister Lavrov in Geneva bear fruit," Obama said.
"But I repeated what I've said publicly, which is any agreement needs to be verifiable and enforceable," he said.