Senior Militant Leader Shot Dead in Islamabad Gunmen killed a senior leader of one of the most feared militant groups fighting U.S. troops in Afghanistan when he stopped to buy fresh bread from a bakery on the outskirts of Pakistan's capital, members of the militant organization and an eyewitness said Monday. Nasiruddin Haqqani's death Sunday night is one of the biggest blows to the Haqqani militant network since the Afghan war started, but the commander's presence in Islamabad and questions over who killed him could spark fresh tension between Pakistan and the United States. U.S. officials have accused Pakistan's intelligence agency of supporting the al-Qaida-linked Haqqani network to counter the influence of archenemy India in Afghanistan - an allegation denied by Islamabad. No one has claimed responsibility for killing Nasiruddin Haqqani in an area of Islamabad only a few kilometers (a couple of miles) from the U.S. Embassy, but some Pakistanis are suspicious the Americans were behind it. That's a contentious allegation in a country angered by U.S. drone attacks targeting militants in Pakistan's tribal region that many see as a violation of state sovereignty. The U.S. Embassy said it was looking into the matter. Nasiruddin Haqqani was a key financier and emissary for the family business. His brother, Sirajuddin Haqqani, currently leads the group, which was founded by their father, Jalaluddin Haqqani, who achieved fame fighting the Soviets in Afghanistan in the 1980s. The U.S. Treasury imposed sanctions on Nasiruddin Haqqani in 2010 when it added him to its list of specially designated global terrorists. The Treasury said he has traveled to Saudi Arabia and the United Arab Emirates to raise money for the Haqqani network, al-Qaida and the Taliban. The gunmen who killed Nasiruddin as he got out of his vehicle outside a bakery in a residential area called Bara Kahu were riding a motorcycle, said witness Tanveer Ahmed. He said he was nearby when the shooting took place but only learned the dead man's identity later. The attack left blood stains on the pavement and bullet holes in the bakery's tiled wall. Ahmed said that when he heard the shooting he first thought it was celebratory fire, which is common at weddings and other events in Pakistan. "But when we reached the spot, some people were shouting, and we saw a vehicle and an injured man lying there where you can see blood on the ground," Ahmed said. Nasiruddin Haqqani's body was taken to the town of Miran Shah in the North Waziristan tribal area, the Haqqani network's main sanctuary in Pakistan, according to a Pakistani Taliban commander, Ahsanullah Ahsan, and an intelligence official said. He was buried Monday, said another Pakistani militant. Two members of the Haqqani network also confirmed that Nasiruddin was killed. The militants and the intelligence official spoke on condition of anonymity because they were not authorized to talk to reporters. The killing comes less than two weeks after a U.S. drone strike killed the leader of the Pakistani Taliban, Hakimullah Mehsud, a day before the Pakistani government planned to invite him to hold peace talks. The Haqqani network is closely allied with the Afghan Taliban and pledges allegiance to their leader Mullah Omar, though it operates fairly independently.