DIPLOMATIC tensions between the West and Russia have deepened after Moscow was accused of blocking chemical weapons inspectors from Douma and engaging in a wider operation to conceal the facts of the poison gas attack.

Theresa May told MPs during her Commons statement on the airstrikes: “The problem is the inspectors are being stopped from their investigation in Douma. The regime and the Russians are preventing them from doing that.

“Moreover, again, the regime has reportedly been attempting to conceal the evidence by searching evacuees from Douma to ensure they are not taking out the region samples that could be tested elsewhere.

“And a wider operation to conceal the facts of the attack is under way supported by the Russians.”

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The Prime Minister explained the Organisation for the Prevention of Chemical Warfare (OPCW) was unable to attribute responsibility for any chemical attack because of a Russian veto at the United Nations Security Council (UNSC) to allow this.

“And last week, in the wake of the Douma attack, it again vetoed a new UNSC resolution to re-establish such a mechanism,” added Mrs May.

The Kremlin denied Russia had engaged in any tampering of evidence.

Foreign minister Sergei Lavrov said: “I can guarantee that Russia has not tampered with the site.”

Earlier, Ahmet Uzumcu, the OPCW’s director general, said its nine-strong inspection team, which has been in Damascus since Saturday, had been told by Syrian and Russian officials there were “security issues,” which prevented their deployment to the suburb of Damascus.

He said: “On Saturday, the team proceeded to Damascus, where they met officials of the National Authority to work out a plan for the deployment.

“The team has not yet deployed to Douma. The Syrian and the Russian officials who participated in the preparatory meetings in Damascus have informed the fact-finding mission team that there were still pending security issues to be worked out before any deployment could take place.”

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Peter Wilson, the British representative to the OPCW, said: “It is imperative that the Syrian Arab Republic and the Russian Federation offer the OPCW fact-finding mission team their full co-operation and assistance to carry out their difficult task.”

The UK delegation to the OPCW, later tweeted: “Unfettered access essential. Russia & Syria must co-operate.”

But Mr Lavrov insisted there was no evidence chemical weapons had been used.

He told the BBC: “There is no proof that on April 7 chemical weapons were used in Douma.

“I cannot be impolite to the heads of other states...but, frankly speaking, all the evidence they quoted was based on media reports and social networks.

“A canister lying on a bed and the bed is intact and the window glass is not broken; look, you need to be a bit more serious.”

He added: “Why strike the day before the OPCW is going to move there and verify the fact which they assert was a fact?”

Meanwhile, the UK Government contemptuously dismissed a suggestion from Russia that it was behind the Douma attack.

Mr Wilson said: “Russia has argued that the attack on Douma was somehow staged or faked. They have even suggested that the UK was behind the attack. That is ludicrous.”

Russian President Vladimir Putin, meanwhile, has said that there could be “chaos” in international relations if the US orders further airstrikes on targets in Syria.

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In a phone call with Iran’s leader Hassan Rouhani, President Putin warned that new strikes may lead to a serious breakdown in relations.

The leaders of both countries also used the phone conversation to describe Saturday’s strikes, which targeted sites near Damascus and Homs, as an illegal “act of aggression”.

And in an interview with the BBC’s HardTalk programme, foreign minister Lavrov again described relations between Moscow and the West as being worse now than at the time of the Cold War.

He pointed out that at least during the Cold War there were channels of communication.

“There was no obsession with Russophobia, which looks like genocide by sanctions,” said the foreign minister as he criticised the approach of Western governments.