The Predator drone has proven to be an effective weapon that offers both real-time surveillance and offensive firepower for troops on the ground.

WASHINGTON — Facing growing pressure to lift the secrecy around targeted killings overseas, the Obama administration is considering shifting more of the CIA’s covert drone program to the Pentagon, which operates under legal guidelines that could allow more public disclosure in some cases.

John Brennan, whom President Barack Obama has nominated to run the CIA, favors moving most drone killing operations to the military, current and former U.S. officials say. As White House counterterrorism adviser for the last four years, Brennan has overseen the steady increase in targeted killings of suspected militants and al-Qaida operatives.

In written comments released Friday by the Senate Intelligence Committee, which is considering his nomination, Brennan said coordination has improved between the CIA and Pentagon. If confirmed, he vowed to work closely with Defense officials “to ensure there is no unnecessary redundancy in ... capabilities and missions.”

The proposed shift follows Obama’s vow in his State of the Union speech Tuesday to be “even more transparent” about the “targeting, detention and prosecution of terrorists.”

Under U.S. law that governs the military, known as Title 10, operations may be kept secret but officials have the option of disclosing them. Under the law applicable for the CIA, Title 50, covert operations require a presidential finding and stay classified unless the president expressly declassifies them.

Given those restrictions, it is uncertain how much more transparency the Pentagon would provide than the CIA. However, many at the CIA would welcome a reallocation of more drone operations to the Pentagon to help the agency refocus on its traditional mission as a spy service. It also could ease mounting congressional concerns about mission creep and a lack of accountability for errors, including civilian casualties.

“Despite all of the demands made on it over the last four years, the CIA has to continually remind itself that it is above all the nation’s global espionage and analysis service,” Michael Hayden, who led the agency from 2006 to 2009, said in an interview.

Some officials see pitfalls in transferring the CIA drone campaign to the military.

Most CIA targeting decisions are based on highly sensitive intelligence from secret informants or other sources. The agency would abhor revealing much about its sources. But if it didn’t, that could undermine military confidence in the targeting information.

“The whole logic of the drone is that you’re not making a split-second decision like a commando on the ground,” said Bruce Riedel, a former CIA officer who has advised the White House about Afghanistan and Pakistan. “You have the luxury of loitering over the target for a long period of time to make sure you’re as confident you can be that you’ve got the right target. The only way that works is if the people running the airplane know everything we know. It seems to me the risk of mistakes goes up, not down, if that is not the case.”

The CIA has never publicly acknowledged its covert drone program. By contrast, the Pentagon has acknowledged flying armed drones in the war zones of Iraq, Afghanistan and Libya. The military also has used remotely-piloted aircraft to surveil Somali pirates at sea, the scene of a recent terrorist attack in Algeria and threats to shipping in the Persian Gulf, among others.

More transparency may cause problems for nations known to host U.S. drone bases, including Afghanistan, Djibouti, Saudi Arabia and soon, Niger, if lethal operations were openly acknowledged, former U.S. officials said. In Pakistan, for example, it’s difficult to see how the U.S. military could openly operate without Pakistani government approval. The CIA’s official silence allows Islamabad to refrain from any involvement and to deny any complicity.

The Pakistani news media and public assume the drone attacks, which are highly unpopular, are American.

But “it’s one thing for everyone to know something, and it’s another for the U.S. government to publicly confirm it,” a former intelligence official said.

Yemen offers greater flexibility. If the military took over all the attacks, U.S. officials would be free to say more in public about them, particularly since the government in Sana supports the program.

The public got a glimpse of the military’s clandestine counterterrorism program in June, when Obama disclosed that U.S. forces had engaged al-Qaida militants in Somalia and Yemen. The disclosure, which did not describe specific operations, was made under the War Powers Act, which requires Congress to be informed about military action.

“The military acknowledges the fact that it takes direct action in these places,” the Obama administration official said, declining to be quoted about sensitive internal deliberations. “Taking lethal action is the military’s job, and they’re really good at it.”