US drone targeted al-Qaida deputy Abu Yahya al-Libi: second-in-command to Ayman al Zawahri, the former Egyptian doctor who took over al-Qaida after Osama Bin Laden's death. Photograph: Anonymous/AP One of al-Qaida's top strategists, Abu Yahya al-Libi, may have been killed in a drone strike in north-west Pakistan, according to intelligence officials. If his death is confirmed it would be the biggest blow to al-Qaida since US special forces killed Osama bin Laden in a secret raid in Pakistan in May 2011. US sources said Libi, a Libyan cleric with a degree in chemistry who has survived previous drone attacks, was a target of a strike early on Monday in the North Waziristan tribal region, home to some of the world's most notorious militant groups. Some US officials describe Libi, whose real name is Mohamed Hassan Qaid, as number two to leader Ayman al Zawahri, the former Egyptian doctor who took over al-Qaida after Bin Laden's death. Pakistani intelligence officials told Reuters they believe Libi may have been among seven foreign militants killed in Monday's strike. One of the officials said Pakistani authorities had intercepted telephone chatter about Libi, an al-Qaida theologian and expert on new media whose escape from a US-run prison in Afghanistan in 2005 made him famous in al-Qaida circles. We intercepted some conversations between militants. They were talking about the death of a 'sheikh'," one of the Pakistani intelligence officials said, referring to the title given to senior religious leaders. They did not name this person but we have checked with our sources in the area and believe they are referring to al-Libi. However, a militant commander in North Waziristan closely associated with foreign fighters said: "He has not been killed. This is not the first time claims have been made about his death. The Americans are suffering heavy losses in Afghanistan so they have resorted to making false claims. It can take months to confirm whether drone strikes have killed an Islamist militant leader because the area of the attack is often sealed off by the Taliban in the lawless north-west of Pakistan. Burials are carried out swiftly in order to hide casualties and identities. If a drone strike did kill Libi, it would bolster the US argument that drones are a highly effective weapon against militants. The Pakistan government says that, while the CIA-run pilotless drone campaign has advantages, it fuels anti-American sentiment in the country and is counterproductive because of collateral damage. Drones are a sticking point in talks between the US and Pakistan aimed at repairing ties damaged by a series of events, including the recent imprisonment of the Pakistani doctor who helped the CIA hunt down Bin Laden. According to reports from North Waziristan, which American government sources did not contest, US-operated drones launched three attacks along Pakistan's border with Afghanistan between Saturday and Monday. Reports from Pakistan said nearly 30 people were killed during the sequence of strikes, including four suspected militants on Saturday, another 10 on Sunday, and 15 people in the strike in which Libi was targeted.