The United States does not know if the leader of the Pakistani Taliban, Hakimullah Mehsud, was killed by a drone strike earlier this week, a senior American envoy said on Saturday. Pakistani officials have said a US drone fired two missiles on Thursday at a compound in northwest Pakistan where Mehsud was believed to have been, but his fate was not known. “I've heard every conceivable version of what's happened and I don't know.” the US special representative to Afghanistan and Pakistan Richard Holbrooke said. “But if he's still alive he's one of the worst people on earth. Absolutely vicious,” Holbrooke told reporters during a visit to the Afghan capital, Kabul. Holbrooke is visiting Afghanistan and Pakistan as part of “routine” consultations with their governments, his office said. If Hakimullah was killed, it could provide a much-needed boost to both Pakistan and the US, which lost seven CIA employees to a suicide bomber in Afghanistan on Dec. 30, the second deadliest attack in the agency's history. The bomber posed with Mehsud in a video that was released after the attack. The government said in August the leader of the Pakistani Taliban had died in a Taliban power struggle after his predecessor Baitullah Mehsud's death. Taliban spokesman Azam Tariq denied the reports of Hakimullah Mehsud's death. Pakistani Foreign Minister Shah Mehmood Qureshi said after meeting Holbrooke on Wednesday that any intensified US drone strikes or US Special Forces presence in Pakistan would threaten ties between the long-time allies. US officials say the drones are an effective weapon against militants. US kills FBI-wanted terrorist in Pakistan strike A US missile strike in Pakistan killed one of the FBI's most-wanted terrorists, a man suspected in a deadly 1986 plane hijacking with a $5m bounty on his head, three Pakistani intelligence officials said. The death would be the latest victory for the CIA-led missile campaign against militant targets in Pakistan's insurgent-riddled tribal belt bordering Afghanistan, a campaign that has recently escalated. One Thursday is believed to have missed Pakistan's Taliban chief. The intelligence officials said Friday that a Jan. 9 missile strike in the North Waziristan tribal region killed Jamal Saeed Abdul Rahim. The FBI's Web site lists him as a Palestinian with possible Lebanese citizenship. The Pakistani officials called him an al-Qaida member, but the FBI site says he was a member of the Abu Nidal Palestinian terrorist group. Rahim is wanted for his alleged role in the Sept. 5, 1986, hijacking of Pan American World Airways Flight 73 during a stop in the southern Pakistani city of Karachi, according to the FBI site. The hijackers demanded that 1,500 prisoners in Cyprus and Israel be released and that they be flown out of Pakistan. At one point, the hijackers shot and threw hand grenades at passengers and crew in one part of the plane. Some 20 people, including two Americans, died during the hijacking. Rahim had been tried and convicted by Pakistan, but he and three suspected accomplices were apparently released in January 2008. All four were added to the FBI list late last year.