London/Moscow: Russia and Britain faced off Wednesday trading accusations at a tense meeting of the world’s chemical weapons watchdog, as Moscow accused British and US secret services of being behind the poisoning of a Russian former double agent.

London slammed as “perverse” a Russian proposal for a joint probe into the poisoning of ex-spy Sergei Skripal and his daughter Yulia with a nerve agent, dismissing it as a “diversionary tactic”.

But Russian officials hit back that accusations of Moscow engineering the attack were a “grotesque provocation … crudely concocted by the British and American security services”.

London rejected any possibility of a joint probe.

British authorities say the Skripals were poisoned with the Soviet-designed nerve agent Novichok in the town of Salisbury on March 4, and said it was “highly likely” Moscow was behind it.

The crisis has sent the long-difficult relations between Russia and the West plummeting to new lows. Both sides have already expelled scores of diplomats.

Britain has also suspended high-level diplomatic contact with Moscow.

Russian foreign intelligence chief Sergei Naryshkin warned Wednesday in a speech in Moscow that both sides must avoid tensions escalating to the dangerous levels seen at the height of the Cold War.

Diversionary tactic

At a closed-door meeting of the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague, convened at the request of Moscow, Russia insisted it was ready to cooperate.

“We consider this is necessary to ensure that this problem is solved within the [international] legal framework,” the Russian embassy to the Netherlands said in a Tweet.

It added that it had won backing from 14 other countries on the OPCW’s governing executive council and its statement was “supported by solid facts by experts in this field”.

But the British delegation to the OPCW said “Russia’s proposal for a joint, UK/Russian investigation into the Salisbury incident is perverse. It is a diversionary tactic.”

Moscow was seeking to “evade the questions the Russian authorities must answer,” it added in a tweet.”

The British defence laboratory analysing the nerve agent revealed Tuesday that it could not say whether the substance came from Russia. Moscow hailed that as a vindication of its repeated denials of involvement.

Russia’s ambassador to the Netherlands and deputy minister for industry and trade Georgy Kalamanov attended the OPCW meeting, along with British chemical weapons expert and acting permanent representative to OPCW John Foggo.

A diplomatic source, who asked not to be named, told AFP that Russia had tabled a motion asking the OPCW to “involve Russia in some way or another in the investigation”.

He described the atmosphere inside the meeting as “heavy” but said the talks were set to continue after a break for lunch.

The OPCW’s experts have taken samples from the site in Salisbury and sent them to certified laboratories for analysis, but are still awaiting the results.

Isolation

“But today the Russians have called a meeting of the executive council even before anything has been published,” the source said.

Under the rules of the Chemical Weapons Convention it is up to Britain to lead the inquiry, with technical assistance from the OPCW which is acting in a “totally independent manner,” the source said.

Russia has accused the West of wanting to put up a new Iron Curtain and warned of a return to the mutual isolation of the Cold War.

For Washington, “fighting the non-existent so-called Russian threat has become a real fixation,” foreign intelligence chief Naryshkin said.

“It has reached such proportions and developed such ludicrous characteristics, that it’s time to talk about the return of the grim times of the Cold War.”

He urged the need “to stop the use of force in relations between states, not to bring matters to a new Cuban Missile Crisis”.

That was a reference to the 1962 standoff between the Soviet Union and the United States that brought the world to the brink of nuclear war.

The Kremlin has also demanded an apology from British Prime Minister Theresa May and her government for implicating Russian President Vladimir Putin in the attack, saying this “idiocy has gone too far”.