White House national security adviser Jake Sullivan has been in touch with Moscow to discuss the respective Russian and U.S. embassies, and the two sides are in talks on the subject, Foreign Minister Sergei Lavrov said on Wednesday.

The two countries' embassies have been severely and reciprocally scaled down in recent years as relations have worsened, notably since Russia seized Crimea from Ukraine in 2014, and especially after Russia launched a full-scale invasion of Ukraine last year, in what it calls a "special military operation".

The number of U.S. diplomatic staff in Russia is now around a 10th of its 2017 level of 1,200, and about half are Marines or other security guards.

Relations arguably plumbed new depths in March with Moscow's arrest of American journalist Evan Gershkovich, who is accredited in Russia with the Wall Street Journal, on suspicion of espionage - a charge his employer and the U.S. administration have dismissed.

There is also no sign of the former Cold War rivals resuming arms control efforts, after President Vladimir Putin in February suspended Moscow's participation in the New Start nuclear weapons treaty, the last remaining U.S.-Russia arms pact.

Scheduled talks on resuming inspections under the treaty had previously been cancelled, with Russia saying there was no point discussing this without including wider strategic questions.

On Wednesday, in the text of an interview with Russian television published by Russia's foreign ministry, Lavrov hinted at some of these.

"No one wants a nuclear war, but it was not in vain that ... counterbalances were created in the form of those treaties that we talked about - (on) anti-missile defence, intermediate and shorter-range missiles and the Treaty on Strategic Offensive Arms [New Start]," he said.

Despite the deep freeze in relations, there have been some signs that contact is being maintained.

Last December, Russia agreed to swap jailed American baseball star Brittney Griner for Viktor Bout, an arms dealer jailed in the United States, after contacts between the two countries' intelligence services.

And on Monday, Lavrov said U.S. Ambassador Lynne Tracy had spoken to Russian representatives and given "signals" that the United States was not involved in the weekend mutiny by Wagner mercenaries, and hoped that Russia's nuclear arsenal would be kept safe.

Lavrov also quoted Tracy as saying the mutiny was Russia's internal affair.

(This story has been refiled to change baseball to basketball in paragraph 10)

(Writing by Kevin Liffey; Editing by Alison Williams and Gareth Jones)