A US drone aircraft fired missiles at militants in Pakistan on Thursday, killing eight of them, Pakistani officials said, as American officials vowed to press forward with such attacks after US forces killed Osama bin Laden in his Pakistani hideout.

The third such strike since bin Laden's killing on May 2 indicated an intensification of the attacks compared with the weeks before the al Qaeda chief was shot dead in the US raid on a compound in the Pakistani garrison town of Abbottabad.

The US bin Laden raid has embarrassed and enraged Pakistan's military and worsened already strained US ties.

In Washington, debate over whether Bush administration interrogation practices helped find bin Laden heated up when Senator John McCain said torture of detained militants did not help track down the al Qaeda leader.

Pakistani officials said they were expecting soon a $300 million payment from the United States for costs incurred in fighting militants in a payment that comes even as US lawmakers question aid to Pakistan after bin Laden was found there.

The drone strikes anger many Pakistanis and are another source of friction between the allies. Pakistan officially objects to the attacks, although US officials say they are carried out on an understanding with Pakistan.

“There are absolutely no plans at present to cease or scale back US counterterrorism operations in Pakistan,” one US official said on condition of anonymity. “Efforts to thwart terrorism will continue.”

A drone fired two missiles at a vehicle in the North Waziristan region on Thursday headed toward the Afghan border, killing eight militants, Pakistani officials said.

The CIA regularly launches attacks with pilotless aircraft at militants in Pakistan's Pashtun tribal lands who cross into Afghanistan to battle Western forces there.

The use of missile-armed Predator drones to attack militants has widened a diplomatic divide with Pakistan and sharpened anti-US anger - but killed few senior militants.

A senior Pakistani security official, asked if Pakistan would take steps to stop the strikes, said there was “nothing of that sort” under way to derail the drone program.

“You have to realize that all (the) equipment you use is theirs, so you can't afford confrontation with them,” the official said on condition of anonymity.

Simulated Drowning

McCain said CIA Director Leon Panetta had told him the trail to bin Laden did not - as some aides to former President George W. Bush have asserted - begin with information from Khalid Sheikh Mohammed, the self-professed mastermind of the Sept. 11, 2001, attacks on the United States who the US government acknowledges was “waterboarded” 183 times.

McCain said he wanted to clear up “misinformation” that could make Americans think harsh treatment of prisoners was acceptable. Waterboarding, a former of simulated drowning, is deemed torture by human rights groups and others.

McCain, who was tortured as a prisoner during the Vietnam War, is an important Republican voice on national security matters and was his party's presidential nominee in 2008.

“In short, it was not torture or cruel, inhuman and degrading treatment of detainees that got us the major leads that ultimately enabled our intelligence community to find Osama bin Laden,” McCain said in the Senate.

Multiple US intelligence officials told Reuters the real breakthrough that led to bin Laden came from a mysterious CIA detainee named Hassan Ghul. Ghul, who was not captured until 2004 at the earliest, was not subjected to waterboarding.

Waterboarding had been phased out by the time he was captured. Two US officials said he may have been subjected to other coercive CIA tactics, possibly including stress positions, sleep deprivation and being slammed into a wall.

It was Ghul, the officials said, who after years of hints from other detainees provided the information that prompted the CIA to focus intensely on finding Abu Ahmed al Kuwaiti, a pseudonym for the courier who would lead them to bin Laden.

The US raid to kill bin Laden has fueled suspicion in the United States that Pakistan knew where bin Laden was hiding, while angering Islamabad, which sees the operation as a violation of its sovereignty.

$300 Million Payment

Pakistani officials said the country was likely to get $300 million from the United States from the Coalition Support Fund, or CSF, a program to reimburse nations that have incurred costs backing counterterrorism and counter-insurgency operations.

The United States has reimbursed Pakistan $7.4 billion under the CSF program since 2001, when Pakistan joined the US-led campaign against militancy. Funds that come in through the CSF are not officially designated as US foreign aid.

Some US lawmakers have called for suspending aid to Pakistan. But President Barack Obama's administration has stressed the importance of maintaining cooperation with Pakistan in the interests of battling militancy.