Ten people pleaded guilty on Thursday to being agents for Russia while living undercover in the United States as part of a spy swap between the US and Russian governments that revived Cold War-era intrigue.
The suspects agreed in court to be deported to Russia. In turn, Russia agreed to release four people imprisoned for suspected contact with Western intelligence agencies, the US justice department said.
The swap helped resolve a scandal that threatened to strain US-Russian relations and revealed shocking details about 10 people living double lives as ordinary citizens while trying to infiltrate US policymaking circles.
Such swaps are not unprecedented but were more a fixture of the Cold War, when the United States and the former Soviet Union were sworn enemies competing for world domination.
Both the Kremlin and the administration of president Barack Obama sought to prevent the arrests from affecting relations that had been improving after hitting lows with Russia's 2008 war against Georgia.
Obama, who hosted Russian president Dmitry Medvedev at the White House last month, needs Moscow's help for efforts to rein in Iran's nuclear program and keep supply lines open for the war in Afghanistan. Russia wants US support to gain entry to the World Trade Organization.
Obama "was fully informed" about the swap and endorsed it, White House chief of staff Rahm Emanuel said on the "PBS NewsHour" program, stressing that the case was pursued by intelligence and law enforcement officials.
Some of the suspects were shown on NBC television boarding a Vision Airlines jet at New York's LaGuardia Airport on Thursday night, and footage from Reuters Television later showed the plane taking off.
Neither the US state department or the US department of justice would comment on the reports.