The Hague, Apr 17 (AFP) Chemical weapons experts are due to arrive in Douma tomorrow to probe an alleged poison gas attack, Russian officials said, as the US voiced fears Moscow may already have "tampered with" evidence at the site.

Following weekend missile strikes on Syria by the US, France and Britain, Russia traded accusations with Western nations yesterday, dismissing as "a blatant lie" accusations that Moscow was hindering the investigation in Douma.

The four nations confronted each other in tense emergency talks at the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague as inspectors prepare for a difficult, dangerous mission.

OPCW director general Ahmet Uzumcu said his nine-strong, all-volunteer team had reached Damascus, but so far "the team has not yet deployed to Douma" -- scene of an alleged chlorine and sarin gas attack on April 7 where 40 people were said to have been killed.

Syrian and Russian officials had warned of "pending security issues to be worked out before any deployment could take place," Uzumcu said.

Igor Kirillov, head of Russia's radiological, biological and chemical protection unit, told reporters the roads still had to be de-mined and cleared and would be tested by UN security services today.

"On Wednesday (tomorrow) is when we plan the arrival of the OPCW experts," he added at a press conference in the Russian embassy in The Hague.

The American ambassador to the OPCW, Ken Ward, claimed however the Russians had already visited the site and "may have tampered with it with the intent of thwarting the efforts of the OPCW fact-finding mission".

The Kremlin dismissed the claims.

"I can guarantee that Russia has not tampered with the site," Russian Foreign Minister Sergei Lavrov told the BBC. And the Russian ambassador to the Netherlands, Alexander Shulgin, said it was a "blatant lie" that Moscow was hampering the investigation.

Instead he said it was the United States, France and Britain who were "standing in the way" of the investigation by ordering air strikes "in the blink of an eye" before the OPCW team had had a chance to do their work.

The missiles that US, French and British warships fired on suspected chemical facilities on Saturday constituted the biggest Western attack against the regime in the seven-year war to topple Syrian President Bashar al-Assad.

The targeted sites were largely empty, and were all said to be facilities for chemical weapons storage or production.

Both British Prime Minister Theresa May and French President Emmanuel Macron faced anger yesterday from their lawmakers for conducting the air strikes with the United States.

Despite polls showing scant support for the move, May said it had been her "responsibility as prime minister to make these decisions," while Macron also defended his move as part of his constitutional powers. (AFP) CK

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