US missiles on Thursday killed Al-Qaeda's chief in Pakistan, one of the Americans' main targets in the volatile country and wanted for attacks that killed scores of people, officials said.

Badar Mansoor, who reputedly sent fighters to Afghanistan and ran a training camp in North Waziristan, was killed in a drone strike near the Afghan border, Pakistani officials and a member of his group told AFP.

"He died in the missile attacks overnight in Miranshah. His death is a major blow to Al-Qaeda's abilities to strike in Pakistan," a senior Pakistani official told AFP, speaking on condition of anonymity.

His death was confirmed by one of his loyalists.

"Badar Mansoor was killed in the missile attack," a militant among his group confirmed by telephone.

Intelligence officials in Miranshah, the main town of North Waziristan, said Mansoor -- whose first name is also sometimes spelled Badr -- had been killed, but other Pakistani officials were divided.

"We're not sure. We cannot give confirmation just like that," one of them told AFP on condition of anonymity.

Four militants were reported killed in the pre-dawn drone strike, which targeted a compound in Miranshah, the main town of North Waziristan.

It was only the second such attack in Pakistan since US President Barack Obama confirmed the secret drone programme late last month.

Pakistan and the United States are currently taking tentative steps to repair a serious crisis in relations over last year's covert American raid that killed Osama bin Laden and US air strikes that killed 24 Pakistani soldiers.

The senior Pakistani intelligence official described Mansoor as the "de facto leader of Al-Qaeda in Pakistan" after his predecessor, Ilyas Kashmiri, was reported killed in a drone strike last June.

Unlike Kashmiri, who had a $5 million bounty on his head, Mansoor is not listed on the US State Department Rewards for Justice list.

There was no immediate confirmation of his death from the United States. But one Western counter-terrorism expert described Mansoor as the local chief of Al-Qaeda and one of the Americans' chief targets in Pakistan.

"If it's true, this is very good news for the anti-terrorism fight, and this was very important for both the US and Pakistan," the official said.

He called Mansoor Al-Qaeda's go-between with Pakistan's umbrella Taliban movement and a member of Al-Qaeda's leadership shura in Pakistan.

Officials said Mansoor was responsible for attacks in Karachi and on the minority Ahmadi community that killed nearly 100 people in the eastern city of Lahore in May 2010.

Ahmadis, considered a sect of Islam, are subject to severe discrimination in Pakistan, which declared them non-Muslims in 1974.

Aged about 40 and from Dera Ghazi Khan in Punjab province, Mansoor moved to Miranshah several years ago to set up his own training camp.

"Western officials believed he was involved in sending fighters to Afghanistan," the senior Pakistani official told AFP.

US officials say Pakistan's tribal belt provides sanctuary to Taliban fighting in Afghanistan, Al-Qaeda groups plotting attacks on the West, Pakistani Taliban who routinely bomb Pakistan and other foreign fighters.

Obama said the drone programme was a "targeted, focused effort at people who are on a list of active terrorists". The founder of the Pakistani Taliban, Baitullah Mehsud, was one of the most high profile casualties, killed in 2009.

But The Bureau of Investigative Journalism, based in London, says there are credible reports that between 282 and 535 civilians, including more than 60 children, have been killed in drone attacks since Obama took office.