US claims al-Qa'ida scalp as drone attack kills terror network's No 2 Abu Yahya al-Libi

Strike in Pakistan follows protests by Islamabad over use of controversial remote-controlled aircraft

The United States claimed a signal victory in its battle to defeat al-Qa'ida yesterday with the killing of a Libyan militant believed to have become No 2 in the network after the death of Osama bin Laden last year.

The White House said the elimination of Abu Yahya al-Libi was a "major blow" to the terror group. As "general manager" of al-Qa'ida, he would be hard to replace or replicate, Jay Carney, spokesman for President Barack Obama, contended. He said his death would speed the demise of al-Qa'ida.

US and Pakistani officials indicated off the record that Abu Yahya had been among several foreign fighters killed in pre-dawn strikes by a US drone on a mud house in North Waziristan in north-west Pakistan on Monday. The killing of Abu Yahya may be counted as the biggest success yet in the eight-year history of clandestine US drone strikes.

"We have confirmation of his death," Mr Carney told reporters, offering no further elaboration. "There is now no clear successor to take on the breadth of his responsibilities." Since the killing of Bin Laden by a Navy SEALs team last year, the US has killed a dozen or more additional senior al-Qa'ida militants using unmanned drones. The US does not comment directly on drone missions, which are covert.

An official in Washington suggested he was "among al-Qa'ida's most experienced and versatile leaders" and had "played a critical role in the group's planning against the West, providing oversight of the external operations efforts". A Pakistani official told Reuters that Abu Yahya had died in hospital after being struck by one of two missiles fired. "We intercepted some conversations between militants. They were talking about the death of a 'sheikh'," the official said, using a title given to senior religious leaders.

The profile of Abu Yahya, who was in his 40s and an Islamic scholar, soared after he escaped from a US military jail at Bagram Air Force Base in Afghanistan in the summer of 2005. Since then he has appeared in dozens of al-Qa'ida videos and following the killing of Bin Laden last year by US Special Forces it was reported that the Libyan had become the group's second-in-command. US officials believe he was one of only a few network commanders in a position to approve terror operations and issue fatwas.

The US had offered $1m for information leading to Abu Yahya as part of its Rewards for Justice Programme. News of his death will be a major boost for backers of Washington's controversial drone programme.

While campaigners in Pakistan say many innocent civilians are killed by the strikes and the military is at least publicly opposed to them, the US has aggressively defended the drone attacks and their frequency has increased during the Obama administration, who reportedly personally approves or vetoes the so-called "kill list" for each strike. There have been eight drone strikes in the past two weeks.

Yesterday, the Pakistani foreign ministry summoned the US ambassador Richard Hoagland to protest at the recent drone strikes. "He was informed that the drone strikes were unlawful, against international law and a violation of Pakistan's sovereignty," a statement from the foreign ministry said.

Mirza Shahzad Akbar, a lawyer who is representing the families of civilians killed by drone strikes in lawsuits against the US, said it was initially reported that six people had been killed in yesterday's operation but that once rescuers reached the area they found that 16 people had been killed.

Regardless of what happened to Abu Yahya, "you have killed another 15 people", he said. "In the last two weeks 56 people have been killed by drone strikes," added Mr Akbar, of the Freedom Foundation group.

Monday's attack struck in Hesokhel, located east of Miranshah, the main town of North Waziristan. Abu Yahya, also known as Mohamed Hassan Qaid, had been operating in this area since his escape from US custody along with three of his cellmates.

Wanted dead or alive: Al-Qa'ida's top men

Abu Yahya al-Libi

Nationality Libyan

Role Believed to be al-Qa'ida's Number 2, key member of the group's Shariah Committee.

Killed by a drone strike in North Waziristan on Monday.

Osama bin Laden

Nationality Saudi

Role Founder and leader of al-Qai'da.

Killed by US commandos in May 2011.

Anwar al-Awlaki

Nationality Duel US-Yemeni citizenship

Role Leader of al-Qa'ida in the Arabian Peninsula.

Killed by US drone strike in Yemen in September 2011.

Saif al-Adel

Nationality Egyptian

Role Senior al-Qa'ida commander

Price on head Up to $5m

Adnan el Shukrijumah

Nationality Saudi

Role Plans global attacks.

Price on head $5m

Ayman al-Zawahiri

Nationality Egyptian

Role Current leader of al-Qai'da – took over after Osama bin Laden's death.

Price on head Up to $25m