NEW YORK (AFP) – Ten alleged members of a Russian spy ring will appear in a US court Thursday, as Moscow and Washington are said to be planning a dramatic Cold War-style prisoner swap.

Lawyers for the accused said Washington and Moscow were discussing a prisoner swap that could come as early as Thursday as a way out of the sticky case, The New York Times reported.

"I feel our discussions will probably be resolved by tomorrow one way or another," Robert Baum, a lawyer for Anna Chapman, one of the suspects, told the daily Wednesday after speaking with US prosecutors and Russian officials.

The alleged Russian "deep cover" sleeper agents were arrested June 27 in an FBI swoop that recalled shadowy Cold War hostilities and threatened to upset efforts to reset ties between the superpowers.

An 11th suspect, accused Kremlin paymaster Christopher Metsos, remains at large.

With US officials formally charging the suspects Wednesday with acting as illegal foreign agents, judges ordered two of the suspects detained in Boston and three in the Washington area to be transferred to New York, where they will join five already here.

They all were to appear before a judge in federal court, the US prosecutor's office for Manhattan announced.

They are all accused of "conspiring to act as secret agents in the United States on behalf of the Russian Federation," the formal indictment said, adding that nine are also charged with "conspiracy to commit money laundering."

The charges carry maximum sentences of 20 years for money laundering and five for the secret agent allegations.

Moves to gather the alleged spies together in New York came as the Russian and US governments were said to be planning a spy swap to avoid potentially embarrassing and diplomatically damaging court battles.

Russian lawyer Anna Stavitskaya told a press conference in Moscow that her client Igor Sutyagin, jailed in 2004 on charges of spying for the CIA, had been told he would be released as part of the swap.

"He is going to be exchanged for the people who are being accused of espionage in the United States," Stavitskaya said.

Sutyagin, a Russian arms expert, was convicted in 2004 of handing over classified information to the United States, via a British security company that Russia claimed was a CIA cover. He was sentenced to 15 years in jail.

Russian officials and the White House refused to comment on the swap claim. "This is a law enforcement matter that is being handled that way," said White House spokesman Robert Gibbs.

Neither Russia nor the United States wants the case to damage relations and both have a stake in avoiding a prolonged trial that could expose sensitive information to a global media glare.

Sutyagin's brother Dmitry Sutyagin said his brother had told the family that the possible exchange was a US idea.

"The Americans presented a list of people for whom they were ready to exchange the people detained in America accused of espionage. Igor was among them."

Kommersant daily reported Thursday on the apparent list, which it said included Sergei Skripal, a former colonel with Russian military intelligence who it said was sentenced in 2006 to 13 years jail on charges of spying for Britain.

A former spokesman for Russia's Foreign Intelligence Service (SVR), Yury Kobaladze, told Echo of Moscow radio that an exchange would be a "wonderful way out of a very complex situation."

Exchanges of captured agents between Western and Eastern powers were a regular tactic in the Cold War, sometimes on the Glienicke Bridge between East and West Germany.

Adding fuel to the speculation, a US State Department spokesman confirmed that William Burns, a former US ambassador to Moscow, met Wednesday with Russia's US Ambassador Sergei Kislyak.

"It wasn't the main purpose of the meeting, but I believe the case was discussed," spokesman Mark Toner said.

The spy row erupted just three days after US President Barack Obama held a chummy White House summit with Russian counterpart Dmitry Medvedev, but both sides have played down the notion of any diplomatic fallout.

The suspects are accused of being part of the "Illegals" program, a covert operation set up by the SVR, a successor to the Soviet-era KGB, to infiltrate US policymaking circles.

None was charged with the more serious crime of espionage, apparently because there is no proof they passed significant secretive information to their Kremlin spymasters.