WASHINGTON (USA TODAY) -- A Libyan militia leader has been charged in last year's terrorist attacks on the U.S. consulate in Benghazi that left U.S. Ambassador Chris Stevens and three other Americans dead, two federal officials said.
Ahmed Kattalah is the first person to be charged in the Sept. 11 incident that sparked a political firestorm about the initial U.S. response to the assault.
Because the charges remain under seal, the officials were not authorized to comment publicly.
The Justice Department declined to comment on specific charges Tuesday.
"The department's investigation is ongoing,'' Justice spokesman Andy Ames said. "It has been, and remains, a top priority. We have no further comment at this time."
Ahmed Kattalah has been described as the founder of Ansar al-Sharia, a Libyan extremist group. NBC said investigators have been saying for months that they believe he was at the consulate during the attack.
The Obama administration has come under strong attack from some conservatives in Congress who accuse it of covering up failures to secure the consulate before and during Sept. 11, 2012, attack.
Since May, Attorney General Eric Holder and FBI Director Robert Mueller have told lawmakers that the ongoing investigation was bearing fruit.
"We are at a point where we have taken steps that I would say are definitive, concrete and we will be prepared shortly, I think, to reveal all that we have done,'' Holder told the House Judiciary Committee in May. "We have made very, very, very substantial progress in that investigation.''
A month later, Mueller told the same panel: "We've had some success that I can't get into today.''
Meantime, CIA Director John Brennan made public his letter to CIA employees who survived the attacks on U.S. facilities in Benghazi, Libya, requesting they share their firsthand accounts with the congressional intelligence committees.
In the letter dated May 30, 2013, released to The Associated Press by the CIA, Brennan tells his employees that lawmakers asked to hear from them directly. But he adds that speaking to Congress is "completely voluntary" and can be done either through the CIA or confidentially, without informing CIA management.
The disclosure follows media reports that the CIA has been preventing employees from talking to lawmakers about the incid