The US Senate Committee on Intelligence has grilled John Brennan, nominee for the director of the Central Intelligence Agency.
Thursday's confirmation hearings in Washington began with questioning about the controversial policies of drone strikes and harsh interrogation techniques, including waterboarding, which was made popular during the tenure of George W Bush, former US president.
"I did not take steps to stop the CIA's use of those techniques. I was not in the chain of command of that programme," Brennan told the hearing.
"I had expressed my personal objections and views to some agency colleagues" about waterboarding, a form of simulated drowning, nudity and other techniques, he said to the Senate Committee.
His questioning was briefly stalled as protesters yelled objections to US drone strikes and harsh interrogation methods, prompting the committee chairman to clear the room.
Brennan, who had served in the US intelligence agency under Bush, is currently a counterterrorism adviser to President Barack Obama.
"I did not try to stop it, because it was something that was being done in a different part of the agency under the authority of others, and it was something that was directed by the administration at the time," he said.
Access to classified memo
Democrats repeatedly questioned Brennan about Washington's use of armed, unmanned aircraft known as drones.
They pressed their demand that the White House provide them with more of the legal documents underpinning its position that Obama can order lethal strikes overseas on US citizens suspected of terrorist activity.
Brennan said there is a "misimpression by the American people" who believe drone strikes are aimed at suspects in past attacks.
Instead, he said, the United States "only take such actions as a last resort to save lives'' when there is no other alternative in what officials believe is an imminent threat.
On Wednesday Obama directed the Justice Department to give congressional intelligence committees access to a classified memo on the topic.
Senator Dianne Feinstein, Intelligence Committee chairwoman, complained to Brennan that the committee's staff had been banned from seeing the administration's classified legal opinion.
Brennan, 57, said the limited access was necessary because of the "exceptional" nature of the issue.
Jay Carney, White Hose spokesman, said the White House does not plan to send the Justice memos to legislators beyond those on the House and Senate intelligence committees.
Despite the intense questioning, Al Jazeera's Kimberly Halkett, reporting from Washington, said, "it does appear that very shortly John Brennan will be confirmed".
Brennan has been central in overseeing drone policy in Obama's administration.
Obama had wanted to pick Brennan for CIA director shortly after his 2008 election, but his chances were derailed mainly by liberal critics over the interrogation techniques used on some terrorism suspects in the wake of the September 11, 2001, attacks.