Brussels  - NATO's relationship with Pakistan must become closer to ensure security in Afghanistan, the head of NATO said at a meeting with alliance defence ministers on Friday in Brussels.

At their meeting, the ministers "discussed how to step up our help to build Afghan capacities (and) coordination with the other actors on the ground and Pakistan, which must develop more fully," NATO Secretary General Jaap de Hoop Scheffer said.

In recent weeks NATO leaders have expressed concern at a series of deals between the Pakistani government and tribal groups in the restive north of the country, saying they fear that those deals could allow militants in Afghanistan to set up safe havens in Pakistan.

And tensions between Islamabad and the United States, NATO's most powerful member, soared on Wednesday after a US air strike inside Pakistani territory killed 11 Pakistani soldiers.

Although the US air strike was not technically under NATO command, Pakistan's Foreign Minister Shah Mehmood Qureshi protested to Scheffer about the incident at a meeting in Paris on Thursday.

Scheffer refused to comment on the airstrike, but said that he and Qureshi had "agreed that what we need with Pakistan is first of all a strengthening of military-to-military dialogue, (and) secondly, that we do need also a more mature political dialogue between Pakistan and the international community."

"It's crystal clear that that border presents problems, we have seen this increase in people crossing the border and making mischief in Afghanistan and then going back," Scheffer said.

"But in the political dialogue, I do consider Pakistan part of the solution. I will not start a discussion on the assumption that Pakistan is part of the problem," he said.

NATO currently maintains some 52,700 troops in the UN-mandated International Security Assistance Force (ISAF) in Afghanistan, but manning issues remain a problem.

Scheffer said that ministers had made "many more troop offers" in recent weeks, but that he was "still not happy, because we need still more." (dpa)