The most senior US military officer has accused Pakistan's spy agency of supporting the Haqqani group in last week's attack on the US Kabul embassy.
"The Haqqani network... acts as a veritable arm of Pakistan's Inter-Services Intelligence Agency," Adm Mike Mullen told a Senate panel.
Some 25 people died in last Tuesday's 20-hour attack on Kabul's US embassy and other official buildings.
Pakistan's interior minister earlier denied links with the Haqqani group.
Rehman Malik told the BBC Pakistan was determined to fight all militants based on its border with Afghanistan.
Pakistani officials have consistently denied links with militant groups.
US-Pakistan ties deteriorated sharply after the killing of al-Qaeda chief Osama Bin Laden on Pakistani soil by US commandos in May.