WASHINGTON  The Central Intelligence Agency in 2004 hired outside contractors from the private security contractor Blackwater USA as part of a secret program to locate and assassinate top operatives of Al Qaeda, according to current and former government officials.

Executives from Blackwater, which has generated controversy because of its aggressive tactics in Iraq, helped the spy agency with planning, training and surveillance. The C.I.A. spent several million dollars on the program, which did not successfully capture or kill any terrorist suspects.

The fact that the C.I.A. used an outside company for the program was a major reason that Leon E. Panetta, the C.I.A.’s director, became alarmed and called an emergency meeting in June to tell Congress that the agency had withheld details of the program for seven years, the officials said.

It is unclear whether the C.I.A. had planned to use the contractors to actually capture or kill Qaeda operatives, or just to help with training and surveillance in the program. American spy agencies have in recent years outsourced some highly controversial work, including the interrogation of prisoners. But government officials said that bringing outsiders into a program with lethal authority raised deep concerns about accountability in covert operations.