Ban told a closed-door meeting of the UN Security Council Monday that investigators have "now confirmed, unequivocally and objectively that chemical weapons have been used in Syria."

"This is a war crime," he added. "I trust all can join me in condemning this despicable crime."

Ban urged the Council to impose "consequences" should Syrian President Bashar al-Assad fail to hold to a US-Russia brokered agreement to destroy the country's chemical weapons stockpile.

In a press conference later, Ban said most samples tested showed sarin had been used and that the results were "beyond doubt."

Sarin used

On the first page of their report, inspectors said "the environmental, chemical and medical samples we have collected provide clear and convincing evidence that surface-to-surface rockets containing the nerve agent sarin were used."

Chief UN chemical weapons investigator Ake Sellstrom (pictured above) handed over the report to Secretary-General Ban Ki-moon on Monday.

"The conclusion is that chemical weapons have been used in the ongoing conflict between the parties in the Syrian Arab Republic... against civilians, including children, on a relatively large scale," the text said.

The US and Syrian opposition activists say some 1,400 people died in the attack on August 21, which they blame on the forces of Assad.

On Monday, Paulo Sergio Pinheiro, head of an independent commission inquiry set up by the UN Human Rights Council, said some 14 different alleged chemical attacks in Syria were being investigated.

'Strong and binding' resolution

Earlier, Britain, France and the US on Monday called for there to be a speedy "strong and binding" UN resolution committing Syria to the surrender of its chemical weapons stocks.

"If Assad fails in time to abide by the terms of this framework, make no mistake, we are all agreed - and that includes Russia - that there will be consequences," said US Secretary of State John Kerry at a news conference with his British and French counterparts.

However, there was disagreement with Russia about the consequences of Damascus failing to comply, with Moscow cautious about any wording that might stipulate punitive measures. Russian Foreign Minister Sergei Lavrov said such an approach threatened to derail the Geneva-2 peace talks proposed by Russia and the US.

"If for someone it is more important to constantly threaten, to scare, to seek for an excuse for strikes... that is another path to wrecking completely the chances of calling the Geneva-2 conference," Lavrov said.

The Russian minister said he remained convinced that the US would adhere to an agreement announced on Saturday by himself and Kerry. Under the proposed deal, Syria would hand over its chemical weapons for destruction by mid-2014.

rc/dr (AFP, AP, Reuters)