Brian Patrick Regan, 39, appeared in federal court in suburban Alexandria, Virginia in a green prison jumpsuit, accompanied by his attorney, and said nothing during his brief proceeding.
"We enter a plea of not guilty and request a trial by jury," said his attorney, Nina Ginsberg.
It wasn't the first time Regan had been charged, or given a pleading.
He pleaded innocent in November to a charge of attempting to give national secrets to another country. That indictment did not identify the country, but intelligence sources said at the time that it was Libya.
"We believe we had a serious defense before the superseding indictment and we continue to believe in that defense," Ginsberg told The Associated Press after the hearing before U.S. District Judge Claude Hilton.
That re-indictment of Regan, announced in Washington Thursday by Justice Department officials, said the retired serviceman with thousands of dollars in debts sought dlrs 13 million from Iraqi President Saddam Hussein in exchange for sensitive U.S. military secrets, and also offered to spy for Libya and China.
Bitter over "the small pension I will receive for all of the years of service," Regan allegedly wrote to Saddam that the payment demand was a "small price to pay," the government said as it lodged new criminal charges in the nation's latest espionage case.
Regan could face the death penalty. A grand jury in Alexandria indicted him Thursday on three counts of attempted espionage and one of gathering national defense information.
Deputy Attorney General Larry Thompson declined to say whether Regan turned over any secret or otherwise classified information to foreign governments. Thompson also declined to say whether Regan actually delivered the letter he is accused of writing to Saddam.
But the indictment indicated that Regan in June flew to Berlin and possibly Munich before returning to Washington seven days later, and the trip was "not in connection with any official duties."
Prosecutors said Regan wrote personally to Saddam sometime between 1999 and 2001 and asked for dlrs 13 million in Swiss currency to provide information about U.S. satellites and other military secrets. Prosecutors said he offered to send a sample of secrets for dlrs 1 million, and offered additional information afterward for dlrs 3 million and dlrs 5 million payments.
Thursday's indictment also accused Regan of writing a nearly identical letter to Libyan leader Moammar Gadhafi between August 2000 and August 2001, but it apparently did not include demands for payment. That letter offered Gadhafi top-secret information about satellites, early warning systems and overall U.S. defense strategies, prosecutors said.