Washington: Sharply criticising Pakistan for failing to rein in terrorist and militant groups on its soil, NATO has asked Islamabad to do more to take action on insurgents who are based on its territory but operate in Afghanistan.

"Pakistan needs to align itself with NATO mission in Afghanistan by denying  militants a chance to regroup on its territory," NATO spokesman Brig Gen Carsten Jacobsen said.

The comments of the NATO-led top ISAF commander come as Washington is softening its tone on Pakistan.

"Whether it is Haqqani, or whether it is the Taliban that are looking for safe havens and training facilities in Pakistan, they have to be fought by all of us – Afghanistan, Pakistan, and the international community," the spokesman was quoted by Voice of America as saying.

"Pakistan has done a lot against terrorists and insurgents, and paid a considerable price in blood over the last years. There is no question that it is not enough," he said.

Last month, just before retiring, US Joint Chiefs of Staff Chairman Admiral Mike Mullen - the highest commander of the US military - called the Haqqani network a "veritable arm" of Pakistan's military intelligence agency, the ISI.

Mullen's remarks galvanised anti-American sentiment in Pakistan and drew sharp reactions from an all-parties conference convened by the Pakistani president. The admiral's allegations also fuelled US lawmakers' skepticism about the future of American aid to Pakistan.

However, senior US diplomats now appear to be adopting a more conciliatory tone about US-Pakistan cooperation in the fight against terrorists.

US Special Representative for Afghanistan and Pakistan Marc Grossman is due later this week in Islamabad. In a interview in Kabul on Saturday, he emphasised that 19,000 Pakistani civilians have been killed since 2003.

Grossman says the conversation between the United States and Pakistan is now focused on "how to get our interests shared and then act on them together," and stressed the need for engagement between the United States and Pakistan.

Grossman says Washington will continue "to call on Pakistan to end the safe havens and enablers" that allow militants to carry out guerrilla raids in Afghanistan, then retreat to Pakistan.