ISLAMABAD, Pakistan — Britain and America have been urged to prepare an exit strategy from Afghanistan by sources within the Pakistan government as the number of fatalities among NATO forces fighting the Taliban grows.

The remarks, by a senior foreign ministry official, reflect the growing belief in Islamabad that NATO is as much to blame for the endurance of the Islamic rebel army as Pakistan, which has been accused by the United States of failing to destroy Taliban training camps on its border.

NATO has had to review tactics after a series of blunders in which large numbers of civilians were killed in raids intended to hit Taliban fighters.

The Afghan government has claimed that the attacks acted as a recruiting sergeant for the rebels seeking to restore a hardline Islamic regime.

Khurshid Kasuri, Pakistan’s foreign minister, said Thursday that NATO should consider holding talks with Taliban leaders.

“They should take a holistic approach — the military is an essential component but it has to be coupled with a political process and development,” he said.

Mr. Kasuri added that the upper house of the Afghan Parliament had shown the way “by speaking about the need to talk to some of the people who have taken up arms.”

Mr. Kasuri said that Britain in particular should know the limitations of a purely military approach in Afghanistan.

“Britain has a good experience of the country, after all they fought three Afghan wars,” he said. “Surely they have learnt from that.”