Militants fighting NATO forces in Afghanistan are also trying to destabilise Pakistan, and the alliance should therefore take a more regional approach to the Afghan conflict, NATO's chief said on Thursday.

NATO needed to bolster its contacts with Pakistan because its stability was crucial to the success of the NATO's Afghan mission, NATO Secretary-General Jaap de Hoop Scheffer said.

"We should increase military-to-military engagement in Pakistan and deepen the political dialogue," de Hoop Scheffer told reporters at the start of a two-day meeting of NATO defence ministers in the Polish city of Krakow.

"I can say again that I believe the Pakistani government is serious about fighting extremism. What we need in NATO is to stop seeing Afghanistan in isolation and to start seeing it in a more regional approach."

"That is why we deepen our cooperation with Pakistan because the same people are trying to destabilise the situation in Afghanistan and in Pakistan," Scheffer added.

NATO heads an international force battling Taliban militants in Pakistan's neighbour Afghanistan. The Pakistan army is struggling to quell Taliban insurgencies dotted across its own northwest region.

Earlier this week, NATO expressed concern after Pakistan signed a pact with Islamists to introduce Islamic law in the northwestern Swat valley in an effort to take the steam out of a Taliban uprising there.

Western officials fear the move will only encourage Islamist militancy in the region at a time when U.S. President Barack Obama has ordered 17,000 more troops to go to Afghanistan.

On Thursday, the radical Muslim cleric who prised the offer from Pakistan's government to restore Islamic law in the Swat valley, Maulana Sufi Mohammad, sent emissaries to his Taliban son-in-law to seek peace in the region.

At the NATO meeting in Poland, the United States will urge its allies to increase their commitments in Afghanistan.