Thirty-seven people were killed when a fire swept through a wooden psychiatric hospital in northwest Russia overnight Thursday, in the latest tragedy to hit the country's mental health institutions.

The fire was started by a patient who was either smoking or deliberately set fire to his bed at the hospital in the village of Luka, 220 kilometers (137 miles) southeast of Saint Petersburg, officials said.

Russian Foreign Minister Sergei Lavrov said Thursday that Syria handing over chemical weapons and joining the treaty banning them would make U.S. strikes against the country "unnecessary," as U.S. Secretary of State John Kerry rejected a 30-day timetable suggested by Syrian President Bashar Assad to begin submitting data on his chemical arsenal.

Lavrov told journalists ahead of talks with Kerry that their goal is to agree how to "solve once and for all the problem of chemical weapons in Syria" through the country's joining of the chemical weapons convention.

President Vladimir Putin won't be getting a check from The New York Times as a "freelance journalist" but his controversial article on Syria was accepted for its newsworthy viewpoint.

The newspaper's public editor Margaret Sullivan said Thursday that the Russian leader's editorial, submitted via a U.S. public relations firm, created "a major stir, including plenty of criticism."

Russia on Thursday said it was carrying out raids as part of a probe into the alleged embezzlement of $1.5 million of state funding allocated for refitting Saint Petersburg's celebrated Hermitage museum.

The interior ministry said its investigators were probing the embezzlement of 50 million rubles ($1.5 million, 1.1 million euros) from the federal budget intended for reconstruction work at the museum renowned for its priceless collection of Western art.

Destroying Syria's chemical weapons under a Russian plan would be "immensely difficult" and may do little to end the conflict there, the International Institute for Strategic Studies (IISS) said on Thursday.

Russia and Iran would have to play a role in dismantling the chemical arms stockpiled by the regime of President Bashar Assad in a process that would take years, said experts from the London-based think-tank.

The rebel Free Syrian Army categorically rejected Thursday a Russian proposal for placing Syria's chemical arms under international control, and called for regime officials to be brought to justice.

The Syrian National Coalition opposition group also questioned the initiative, calling it a "political manoeuvre aimed at buying time" for the regime of President Bashar Assad.

President Bashar Assad said Thursday Washington must stop arming rebels and stop threatening military force if it wanted a plan for Syria to hand over chemical weapons to work.

"When we see that the United States truly desires stability in our region and stops threatening and seeking to invade, as well as stops arms supplies to terrorists then we can believe that we can follow through with the necessary processes," he told Russian television, adding that Washington should dispense with the "politics of threats."

Russian Foreign Minister Sergei Lavrov on Thursday said there was still "a chance for peace" in Syria as he prepared for high-stakes talks with his U.S. counterpart on a plan for Damascus to give up its chemical weapons.

Before leaving for the talks in Geneva, Lavrov said during a visit to Kazakhstan that he was prepared to "ensure Syria's adherence to the chemical weapon ban convention," which would include the country's total disclosure of its chemical arms sites.

Washington called Thursday on the Syrian regime to quickly declare the scope and size of its chemical weapons stockpile as Secretary of State John Kerry arrived in Geneva for high-stakes talks.

A senior U.S. official said the aim for the talks with Russia was "to see if in fact we can test whether there is a credible and authentic way forward here, that the Russians mean what they say... and probably more importantly that Assad means what he says."

Russian protest leader Alexei Navalny on Thursday sent a car-load of complaints to court contesting the results of Moscow's mayoral election, as President Vladimir Putin was due to attend the inauguration of his ally as city chief.

Incumbent mayor Sergei Sobyanin, a Kremlin ally who barely avoided a run-off in Sunday's closer-than-expected vote, is due to be sworn in for a new term Thursday evening in front of hundreds of guests led by Putin.