The US does not regularly comment on drone attacks
A key al-Qaeda figure wanted for a deadly attack on a CIA base in Afghanistan has been killed in a US drone strike, US officials believe.
Hussein al-Yemeni, a top al-Qaeda planner, died in the strike in the city of Miranshah in Pakistan, they said.
He was believed to have helped plan an attack on a base in Khost in December in which a suicide bomber killed seven CIA agents and a Jordanian officer.
The CIA's director has said al-Qaeda is now in disarray in Pakistan.
The BBC's M Ilyas Khan in Islamabad says drone strikes have put foreign fighters in Pakistan under pressure in recent months.
There are also indications that the Taliban may be in the process of disengaging from hardcore foreign militants in order to present themselves as legitimate participants in any talks on sharing power in Afghanistan, our correspondent says.
'On the run'
A US counter-terrorism official told Agence France-Presse news agency that the drone strike in Miranshah, in North Waziristan, was "a clean, precise action that shows these killers cannot hide even in relatively built-up places".
Yemeni was said to be in his late 20s or early 30s and specialised in "bombs and suicide operations", the official said.
"He was a conduit in Pakistan for funds, messages and recruits," he said.
Yemeni had contacts with al-Qaeda in the Arabian Peninsula and Afghan and Pakistani Taliban groups, US officials believe.
The attack on the CIA on 30 December was the worst against US intelligence officials since the American embassy in Beirut was bombed in 1983.
The dead included the head of the CIA's base in Khost Province.
The Taliban said one of their members wearing an explosive vest and an army uniform had carried out the attack.
A US official said at the time that the bomber was being courted as an informant and was not frisked as he entered Forward Operating Base Chapman.
Leon Panetta says that al-Qaeda is now "scrambling"
In an interview with the Washington Post on Wednesday, CIA Director Leon Panetta said attacks against al-Qaeda had left it unable to plan sophisticated operations.
"It's pretty clear from all the intelligence we are getting that they are having a very difficult time putting together any kind of command and control, that they are scrambling. And that we really do have them on the run," Mr Panetta said.
He said that the attacks had been so effective that an al-Qaeda lieutenant had pleaded in an intercepted message to Osama Bin Laden that the al-Qaeda leader needed to come to provide some leadership.
Hundreds of people, including a number of militants, have been killed in scores of drone strikes since August 2008.
Pakistan has publicly criticised the drone attacks, saying they fuel support for militants.