Ten suspected Russian spies in the United States could enter guilty pleas Thursday and be swiftly deported, possibly as soon as Thursday night, a source with detailed knowledge of the investigation told CNN.

The source said the suspects are expected to plead guilty in federal court in New York to one of the current charges against them - failing to register as a foreign agent - and will likely be sentenced to time already served since they were arrested at the end of June.

The development comes amid reports of a possible exchange of the accused Russian spies in the United States for convicted Russian spies in Russia.

One of those Russians - a man convicted of spying for the United States in 2004 and possibly on a list for the swap - left Russia earlier Thursday and arrived in Vienna, Austria, Russia's state-run news agency RIA-Novosti reported. The scientist's family told CNN he was part of the exchange.

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