WASHINGTON - The House Intelligence Committee has asked the CIA to provide documents about the now-cancelled program to target al Qaeda leaders, U.S. congressional officials said Tuesday.

The move is a precursor to what will almost certainly become a full-blown investigation into the secret operation and why the program was not disclosed to Congress, said the officials, who spoke on condition of anonymity because they were not authorized to discuss the matter publicly.

CIA Director Leon Panetta told Congress on June 24 that he had cancelled the effort to kill al Qaeda  leaders with hit teams soon after learning about the operation. Panetta also told lawmakers that former Vice-President Dick Cheney directed the CIA not to inform Congress of the specifics of the secret program.

Intelligence officials say the operation never progressed passed a planning stage and therefore didn't merit congressional notification.

President George W. Bush authorized the killing of al Qaeda leaders in 2001. Congress was aware of that notification.

A congressional official said the secret CIA program was meant to carry out ground attacks. Most attempts to kill al Qaeda's leaders, believed to be hiding in Pakistan's troubled western border region, have used armed drone aircraft because it is difficult terrain controlled by sometimes hostile tribes. But those strikes have sometimes killed and injured innocent civilians and caused outrage in Pakistan.

House Intelligence Committee Chairman Silvestre Reyes, D-Texas, is expected to decide as early as Tuesday whether to press ahead with a full investigation into the CIA operation.

The House Intelligence Committee will try to establish how much was spent on the effort, whether any training was conducted, and whether there was any officials travelled in associated with the program, a committee official said.

Those factors would determine whether the program had progressed enough to warrant congressional notification, the official said.

Sen. Russ Feingold, a Democrat, said Monday that the CIA's failure to brief congress violated the law.

Rep. Peter Hoekstra, the top Republican member of the committee, told The Associated Press on Tuesday that he would support an investigation. But from what he knows now, Hoekstra said, he does not believe the effort merited congressional notification.

Like many other Republicans, Hoekstra believes the Democratic anger about not being notified of the program sooner is meant to bolster the leader of the House, Speaker Nancy Pelosi, who came under an avalanche of Republican criticism in May for saying she believes the CIA lied to her about its harsh interrogation program in 2002.

The House has delayed floor debate on an intelligence bill that would require the president to expand the number of members of Congress briefed on covert operations-- that is, secret missions undertaken in foreign countries to affect their political, military or economic situation.

The White House has threatened to veto that bill if it includes the notification requirement. Current law allows the president to notify top members in the House and Senate and on the intelligence committees on the most sensitive operations.