The spy scandal in the United States is moving toward a swift end this morning, with 10 Russian agents set to be deported after all pleading guilty in a Manhattan courtroom.

A judge ordered all 10 of the spies to be immediately expelled from the US and said they must never attempt to return, in the biggest spy swap deal since the end of the Cold War.

In exchange, Russia will release four prisoners of US interest, including Russian scientist Igor Sutyagin, who has been serving a prison sentence for passing information to the CIA.

Sutyagin's lawyer said her client may already have been released from a Russian jail and taken to Vienna, Austria, as part of the deal.

The spy swap is believed to have been sewn up in talks between the Russian ambassador and a senior US state department official.

In pleading guilty to being foreign agents, the 10 "will have to agree to immediate removal," Judge Kimba Wood said in New York.

That meant "immediate expulsion from the United States" and the defendants would have to "agree never to attempt to return to the US".

Speaking outside the courtroom, the lawyer for Anna Chapman, one of the Russian agents, said his client was not afraid to be returned to Russia and said he expected the spy swap to be carried out within the next 24 hours.

The US Justice Department confirmed the deal with Russia.

"The key provision of the United States-Russia agreement is that the Russian Federation has agreed to release four individuals who are incarcerated in Russia for alleged contact with Western intelligence agencies," a Justice Department statement said.

The suspects each pleaded guilty to one charge of conspiracy to act as an unregistered agent of a foreign country.

A spokeswoman for Russian president Dmitry Medvedev confirmed that the Kremlin was pardoning four Russians, including Sutyagin.

Three of the prisoners who will be released in Russia were reportedly convicted of treason and are serving lengthy prison terms.

The 10 spy suspects were arrested on June 27 in an FBI swoop in Boston and the New York and Washington areas.

They were accused of being members of a "deep-cover" spy ring tasked by the Russian secret service with infiltrating US policy-making circles.

An 11th suspect, accused paymaster Christopher Metsos, remains at large after vanishing last week in Cyprus following a court decision to release him on bail.

-ABC/wires