GENEVA - A U.N. human rights expert accused the U.S. government Wednesday of sidestepping his questions on its use of armed drones to carry out targeted killings overseas.

Christof Heyns, the U.N.'s independent investigator on extrajudicial killings, had asked the United States to lay out the legal basis and accountability procedures for the use of armed drones. He also wanted the U.S. to publish figures on the number of civilians killed in drone strikes against suspected terror leaders in Afghanistan, Pakistan, Yemen and elsewhere.

After a two-day "interactive dialogue" with U.S. officials at the United Nations in Geneva, Heyns said he was still waiting for a satisfactory reply.

"I don't think we have the full answer to the legal framework, we certainly don't have the answer to the accountability issues," he told reporters on the sidelines of a U.N. Human Rights Council meeting.

U.S. officials didn't explicitly mention the use of drones in the debate, but a written submission to the council cited three speeches by U.S. administration officials that discussed counterterrorism operations.

In one of those speeches, U.S. President Barack Obama's counterterrorism chief John Brennan acknowledged in April that the U.S. uses remotely piloted aircraft to conduct targeted killings of suspected al-Qaida members "in order to prevent terrorist attacks on the United States and to save American lives."

Brennan said the attacks were a legal, ethical and wise way of conducting sensitive counterterror operations.

But the U.S. use of armed drones has provoked anger abroad, particularly in Pakistan, where human rights groups say innocent people have been among the victims of the strikes.

The American Civil Liberties Union told the U.N. rights body Wednesday that "the United States has cobbled together its own legal framework for targeted killing, with standards that are far less stringent than the law allows."

It warned that other nations might embrace the U.S.'s justification for the use of drones and also begin carrying out airstrikes on foreign territory.

"My concern is that we are dealing here with a situation that creates precedents around the world," said Heyns, the U.N. investigator.

News from © The Associated Press, 2012