Updated

France on Wednesday dismissed a claim by Russia that a UN report on the use of chemical weapons in Syria was biased, as a row over its contents escalated.

"Nobody can question the objectivity of the people (inspectors) appointed by the UN," Foreign Minister Laurent Fabius told a press conference.

"I'm very surprised by the Russian attitude," he added.

Fabius was speaking after talks with his Spanish counterpart Jose Manuel Garcia-Margallo here against a background of claims and counter-claims related to an August 21 chemical attack which triggered Western threats of military action against the Syrian regime.

Russia said on Wednesday that Syria had given it evidence implicating anti-government rebels in the attack, which Britain, France and the United States have blamed on the forces of President Bashar al-Assad.

Deputy Foreign Minister Sergei Ryabkov said the UN report on the attack that was published on Monday was selective in its assessment of the evidence and had ignored other incidents of chemical weapons use.

"Without a full picture... we cannot describe the character of the conclusions as anything other than politicised, biased and one-sided," he said.

Fabius responded: "The report cannot be seriously contested. It shows that the regime had and still has an significant chemical arsenal and that it used it."

A senior French official said Fabius had delivered a similar message to his Russian counterpart Sergei Lavrov during talks in Moscow on Tuesday.

The Russians did not think "for one second" that the August 21 attack was the work of anyone other than the regime forces, the official said, adding that Moscow was determined to sow confusion to help delay a UN Security Council resolution being prepared in reaction to Monday's report.

Garcia-Margallo said Spain wanted to see a binding Security Council resolution on Syria adopted as possible.