The Obama administration is weighing the possibility of shifting the CIA's controversial drone operations to the military, according to a U.S. official.

The official says there have been discussions within the Obama administration about the shift. The president's senior national security advisers have prepared a proposal in favor of a shift that awaits a final presidential decision, the official said. President Obama has made no decision.

The official says the proposal reflects the move toward more transparency about the CIA's program.

The CIA-administered program targets al-Qaida and Taliban leaders in Pakistan's tribal areas near the border of Afghanistan and al-Qaida in the Arabian Peninsula operatives in Yemen.

The transition could take some time to take place if approved by Obama. The official speculates that it could possibly take years given the complicated politics of the areas where the drones are flying, a reference to Pakistan where the program is hugely unpopular.

Yemen would likely be the first area affected by the transfer.

The official confirmed details first reported by the Daily Beast and the Wall Street Journal that the military would conduct the drone flight operations, but targeting would be a combined effort involving the CIA and other intelligence agencies.

John O. Brennan, the new CIA director, during his confirmation hearing in February, defended the U.S. drone program while calling for greater transparency.

He told the Senate Select Committee on Intelligence that more openness about the program could help the administration clear up what he called "falsehoods" about the program.

He said of the strikes, "We only take such actions as a last resort, to save lives when there is no other alternative."

A top United Nations official recently called the CIA's drone strikes in Pakistan a violation of international law.

"The position of the government of Pakistan is quite clear: It does not consent to the use of drones by the United States on its territory and it considers this to be a violation of Pakistan's sovereignty and territorial integrity," said Ben Emmerson, U.N. special rapporteur on counter-terrorism and human rights.

"As a matter of international law, the U.S. drone campaign in Pakistan is … being conducted without the consent of the elected representatives of the people or the legitimate Government of the State," said Emmerson, who has been investigating the impact of U.S. drone attacks in Pakistan's tribal areas on the civilian population, and is expected to issue a final report to the United Nations soon.