WASHINGTON: Congressional demands for an investigation are growing over new disclosures that a secret CIA program to capture or kill Al-Qaida leaders was concealed from the US Congress for eight years, perhaps at the behest of former Vice-President Dick Cheney.

The program, which never got off the ground and remains shrouded in mystery, was designed to target leaders of the terrorism network at close range, rather than with air strikes that risked civilian casualties, government officials with knowledge of the operation said on Monday.

The officials spoke on condition of anonymity because they were not authorized to discuss it publicly. The program was canceled last month by CIA Director Leon Panetta shortly after he himself first learned of it.