US Secretary of State Hillary Clinton on Thursday demanded that Pakistan dismantle Taliban safe havens, stepping up the pressure on Islamabad as American troops pressed a major offensive along the border.
Clinton spoke in unusually strong language following talks in Kabul with Afghan President Hamid Karzai a month after his peace broker was assassinated, derailing any immediate prospect of reconciliation with the Taliban.
She warned the Taliban to be part of a peaceful future or face a continuing assault, but urged Islamabad to play a "constructive" role in bringing militants to negotiations aimed at ending the 10-year war in Afghanistan.
But many policy makers in Islamabad see a twin US approach of pressing the fight on the battlefield and pursuing reconciliation efforts behind the scenes as contradictory, arguing that Pakistan cannot make any further sacrifices.
Clinton is later due in Pakistan later on Thursday , when she is to be joined by CIA chief David Petraeus and top US military officer Martin Dempsey.
"And now it's a question as to how much cooperation Pakistanis will provide in going after those safe havens," she said.
"We intend to push the Pakistanis very hard as to what they are willing and able to do with us... to remove the safe havens and the continuing threats across the border to Afghans," said Clinton.
She warned militants that "we are going to seek you in your safe havens" on both sides of the Afghan-Pakistani border and confirmed a US operation against the hardline Haqqani network it blames for some of the worst war attacks.
"There was a major military operation inside Afghanistan in recent days that has been rounding up and eliminating Haqqani operatives on this side of the border," Clinton told reporters in a leafy plaza of Karzai's palace.
It is her first visit to the region since a 19-hour siege of the US embassy in Kabul and a truck bombing on a NATO outpost that wounded 77 Americans last month. Washington blamed the attacks on the Haqqanis.
Dempsey's predecessor Admiral Mike Mullen called the Haqqani network the "veritable arm" of Pakistan's Inter-Services Intelligence and accused Pakistani spies of being involved in the embassy siege, dramatically worsening ties.
Clinton confirmed that the United States believes the network operates out of a "safe haven in Pakistan".
US commanders say the Haqqanis are their most potent enemy in eastern Afghanistan and increasingly capable of launching high-profile attacks in Kabul. It is an Afghan Taliban faction, loyal to Taliban leader Mullah Omar.
Clinton said her talks in Pakistan will focus on "how to increase pressure on the safe havens there" while at the same time urging Pakistan to support efforts at negotiations.
"We believe that they can play either a constructive or a destructive role in helping to bring into talks those with whom the Afghans themselves must sit across the table and hammer out a negotiated settlement," she said.
"We will be looking to the Pakistanis to take the lead because the terrorists operating outside of Pakistan pose a threat to Pakistanis, as well as to Afghans and others," she said.
Karzai, who has long called on Pakistan to wipe out militant sanctuaries feeding the Taliban insurgency in Afghanistan, spoke of "shifting the focus" of the peace effort to Pakistan.