Under questioning by a federal prosecutor, a former FBI intelligence analyst admitted that for five years he passed classified information gleaned from White House and FBI computers to conspirators he said were trying to overthrow Philippine President Gloria Macapagal Arroyo.
Leandro Aragoncillo, 47, a naturalized US citizen who was born in the Philippines, pleaded guilty on Thursday to a four-count indictment.
The most serious charge, conspiracy to transmit national defense information, can carry the death penalty. But under a plea agreement, Aragoncillo faces 15 to 20 years in prison. Sentencing was scheduled for Aug. 14.
US Attorney Christopher Christie said outside court that the government did not seek the death penalty because no physical harm resulted from the information leak.
However, Christie said: "It was information that had the potential to compromise US national security."
Aragoncillo, a former Marine, worked as a military aide to vice presidents Al Gore and Dick Cheney starting in 1999. After retiring from the Marines, he became a civilian employee of the FBI, working at Fort Monmouth in central New Jersey.
He was arrested last September, along with Michael Ray Aquino, a former Philippine police official who is accused of passing information from Aragoncillo about Philippine leaders to current and former political officials in the Philippines.
Aragoncillo himself did not identify the officials. But according to documents filed in the U.S District Court in Newark, they included former Philippine president Joseph Estrada, opposition Senator Panfilo Lacson and for-mer House speaker Arnulfo Fuentebella. Estrada last week denied suggestions by US prosecutors that he conspired with Aragoncillo to overthrow Arroyo.
Aquino, a Philippine national living in New York, pleaded not guilty last October to an indictment charging conspiracy and acting as an unregistered foreign agent.
His lawyer, Mark Berman, contacted after Thursday's hearing, said Aquino did not know that the material he received from Aragoncillo was classified.