Pakistan must fight militant groups that threaten Afghan, Indian and US interests, US Secretary of State John Kerry said on Tuesday as he offered sympathy for the victims of last month's massacre of children at a Pakistani school.
Nuclear-armed Pakistan has long been suspected by the West of playing a double game, fighting some militants while supporting those its generals have regarded as strategic assets to be used against rivals and neighbours, India and Afghanistan.
Visiting Pakistan after going to India over the weekend, Kerry said all militant groups should be targeted to bring security to the region.
"Terror groups like the Pakistani and Afghan Taliban, the Haqqani network, Lashkar-e-Taiba and other groups continue to pose a threat to Pakistan, to its neighbours and to the United States," Kerry told a news conference in Islamabad, listing some of the most feared groups.
"And all of us have a responsibility to ensure that these groups do not gain a foothold but rather are pushed back into the recesses of (Pakistan's) memory ... Make no mistake. The task is a difficult one and it is not done."
Most US-led forces in neighbouring Afghanistan officially completed their combat mission last month, prompting concern about the stability of the region where insurgents have been increasingly aggressive in past months.
Following last month's attack on the school in which 134 children were killed, Pakistan has promised to stop differentiating between "good" and "bad" militants and to step up operations against their hideouts on the Afghan border.
Speaking at a news conference with Kerry, Pakistani foreign adviser Sartaj Aziz reassured his counterpart that "action will be taken without discrimination against all groups".
But, although observers have noted some progress, most agree that Pakistan has yet to show it is seriously committed to go after all groups equally, including the powerful Haqqani network which attacks targets in Afghanistan from its bases in Pakistan.
"Obviously, the proof is going to be in the pudding," Kerry said. "It will be seen over the next days, weeks, months, how extensive and how successful this effort is going to be."
Aziz said, however, that the Haqqani group's infrastructure had been "totally destroyed" as a result of the Pakistani army's operation in a tribal region that has long been regarded as a safe haven for militants.
"Their ability to operate from here across to Afghanistan has virtually disappeared," Aziz said.
The United States identified Pakistan as a key partner in its war against terror following the September 11, 2001, attacks and has spent billions of dollars on military aid to help the country fight insurgents.
But there is growing consternation in Washington about continuing with the same level of assistance unless Pakistan provided evidence it was using the funds effectively to eliminate militants holed up on its soil.
Kerry said however Washington would provide an additional $250 million in food, shelter and other assistance to help people displaced by conflict in tribal areas.
Aziz made a plea for the United States to keep giving Pakistan money to help rebuild the regions where the Pakistani military has been fighting militant groups.
"We expect our defence forces to remain engaged in counterterrorism operations for some time in the foreseeable future," Aziz said. "Continuation of coalition support fund reimbursements are therefore a valuable support that must continue in the interests of both countries."
Pakistan was deeply scarred by the December attack when gunmen killed the children at the military-run high school in the northwestern city of Peshawar in revenge for an army operation against Taliban hideouts.
Some analysts believe the national revulsion over brutal attack could convince hawks in the military to withdraw support for militants like the Haqqanis.
For its part, the government has reassured the West and its own sceptical public that it is doing everything to eliminate insurgent violence, reinstating the death penalty and expanding military operations in the tribal North Waziristan region.