America's most senior military officer, Admiral Mike Mullen, has said Pakistan's intelligence agency may have had a hand in an attack on the US embassy in Kabul last week.
Some 25 people died in the 20-hour attack on Kabul's US embassy and other official buildings last Tuesday.
Admiral Mullen, chairman of the US Joint Chiefs of Staff, told a Senate panel that the militant Haqqani group acts as a veritable arm of Pakistan's Inter-Services Intelligence Agency.
"With ISI support, Haqqani operatives planned and conducted a truck bomb attack (on 11 September), as well as the assault on our embassy," he said.
Pakistan's interior minister earlier denied links with the Haqqani group, which is one of three allied insurgent factions fighting NATO and Afghan troops under the Taliban banner in Afghanistan.
Rehman Malik told the BBC that says Pakistan is determined to fight all militants based on its border with Afghanistan.