UNITED NATIONS, Sept 16: A UN report on use of chemical weapons in Syria said on Monday the perpetrators of last month`s attack in Damascus had up to 350 litres of sarin gas.

The report by a UN investigating team was submitted to the UN secretary general and sent to member states, a spokesman said.

`Chemical weapons have been used` in the Syria conflict, the report said.

`In particular, 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 in Ein Tarma, Moadamiyah and Zamalka in the Ghouta area of Damascus.

The inspection team, led by Swedish expert Ake Sellstrom, was mandated to report on whether chemical weapons had been used in the August 21 attack and, if so, which chemical agents were used, not on who was responsible.The Syrian rebels and their Western and Arab supporters blame President Bashar Assad`s regime for the attack in the rebel-controlled area of Ghouta in Damascus.

The Assad regime insists that the attack was carried out by rebels.

Some of the hardware used in the attack had Cyrillic lettering, the report said.

While the UN investigation was not assigning blame for the attack, the source said the details in the report would serve as `signs of culpability`.

The United States, Britain, France, and Nato have said that the Syrian regime was behind the attack and that there`s no sign rebels had access to such weapons.

Syria and its ally Russia have blamed rebels. But the UN finding that whoever was culpable had access to such large amounts of sarin could bolster the US argument.

Russia on Monday took the issue with the United States about an agreementreached over the weekend aimed at averting US military action against the Assad regime.

The next step in implementing the agreement is to get a UN resolution.

But on that front, Russian Foreign Minister Sergey Lavrov accused US Secretary of State John Kerry `and his Western allies` of misunderstanding the deal, according to Russia`s state-run ItarTass news agency.

The deal does not say that a UN resolution will be under Chapter 7 of the UN Charter, Mr Lavrov said.

Chapter 7 potentially authorises use of force.

Mr Lavrov said comments by Mr Kerry `show unwillingness to read the document` that Russia and the United States agreed to.

Mr Kerry said that a UN resolution would need to include the possibility of force. `If the Assad regime believes that this is not enforceable, then they will play games,` he said.