CIA officials were proposing to activate a plan to train anti-terrorist assassination teams overseas when agency managers brought the secret program to the attention of CIA Director Leon Panetta last month, according to two U.S. officials familiar with the matter.

The plan to kill top al-Qaeda leaders, which had been on the agency's back burner for much of the past eight years, was suddenly thrust into the spotlight because of proposals to initiate what one intelligence official called a "somewhat more operational phase." Shortly after learning of the plan, Panetta terminated the program and then went to Capitol Hill to brief lawmakers, who had been kept in the dark since 2001.

The Obama administration's top intelligence official, Director of National Intelligence Dennis C. Blair, yesterday defended Panetta's decision to cancel the program, which he said had raised serious questions among intelligence officials about its "effectiveness, maturity and the level of control."

Blair broke with some Democrats in Congress by asserting that the CIA did not violate the law when it failed to inform lawmakers about the secret program until last month. Blair said agency officials may not have been required to notify Congress about the program, though he believes they should have done so.

"It was a judgment call," Blair said in an interview. "We believe in erring on the side of working with the Hill as a partner."