The Obama administration will narrow its controversial drone program in Pakistan to target a short list of high-level terrorists, and aim to end it during the prime minister's current term, senior U.S. officials have told their Pakistani counterparts.

The downsizing of the covert Central Intelligence Agency program reflects Pakistani objections to the strikes and logistical constraints on the spy agency at the end of this year, when U.S. troops are scheduled to pull out of neighboring Afghanistan, according to administration, intelligence and military officials.

Senior U.S. officials said they have discussed the revisions with Pakistani officials in a series of meetings over the past six months. U.S. officials say the goal is to make the drone campaign less of an irritant in the two countries' troubled relations, without preventing the CIA from conducting higher-priority operations during the time the program has left.

The changes fall short of Prime Minister Nawaz Sharif's demands for an immediate freeze in drone strikes. Pakistani officials in Islamabad and Washington weren't immediately available to comment.

Officials say the revision is meant to move the CIA away from what some critics call a "Whac-A-Mole" approach and put the U.S. on a path to end the program, though not as quickly as drone critics and the Pakistani government would like.