John Brennan confirmed as CIA director

The US Senate confirmed counterterrorism expert John Brennan to be the next CIA director on Thursday, filling a third crucial position on President Barack Obama's national security team.

The Senate voted 63-34 with several Republicans flocking to approve Brennan following a dramatic 13-hour filibuster the night before by Senator Rand Paul over the possible use of drones to conduct targeted killings on US soil.

Despite his reservations, Paul was among several Republicans who backed Brennan, the architect of a controversial "targeted killing" policy that has seen targets such as Al-Qaeda operatives killed in Pakistan and Yemen.

The Kentucky senator had delayed up the nomination, seeking clarification from the White House over whether it was US policy to allow the killing by a drone strike of a "non-combatant American citizen on US soil."

He got his answer on Thursday, when US Attorney General Eric Holder wrote to tell Paul that this was not the policy.

The unmanned aerial drone program had emerged as the most contentious element of Brennan's nomination to head the Central Intelligence Agency.

On Tuesday, Holder had said that, while Obama had "no intention" of ordering drone strikes on US soil, the scenario could be possible if there was an "extraordinary circumstance" such as an attack similar to 9/11.

After he received the letter, Paul said that it showed his battle was worthwhile.

The Republican, who began his filibuster of Brennan's CIA nomination shortly before noon on Wednesday, finally yielded the floor after midnight, to a round of applause.

Paul acknowledged that US drone strikes have proven effective in places like Pakistan and Yemen, including a strike on US-born radical preacher Anwar al-Awlaki, whom Paul branded a traitor.

But he added: "if you're going to kill non-combatants, people eating dinner, in America, there have to be some rules."