WASHINGTON, Nov. 18 — A new and classified American military proposal outlines an intensified effort to enlist tribal leaders in the frontier areas of Pakistan in the fight against Al Qaeda and the Taliban, as part of a broader effort to bolster Pakistani forces against an expanding militancy, American military officials said.

If adopted, the proposal would join elements of a shift in strategy that would also be likely to expand the presence of American military trainers in Pakistan, directly finance a separate tribal paramilitary force that until now has proved largely ineffective and pay militias that agreed to fight Al Qaeda and foreign extremists, officials said. The United States now has only about 50 troops in Pakistan, a Pentagon spokesman said, a force that could grow by dozens under the new approach.

The proposal is modeled in part on a similar effort by American forces in Anbar Province in Iraq that has been hailed as a great success in fighting foreign insurgents there. But it raises the question of whether such partnerships, to be forged in this case by Pakistani troops backed by the United States, can be made without a significant American military presence in Pakistan. And it is unclear whether enough support can be found among the tribes, some of which are working with Pakistan's intelligence agency.

Altogether, the broader strategic move toward more local support is being accelerated because of concern about instability in Pakistan and the weakness of the Pakistani government, as well as fears that extremists with havens in the tribal areas could escalate their attacks on allied troops in Afghanistan. Just in recent weeks, Islamic militants sympathetic to Al Qaeda and the Taliban have already extended their reach beyond the frontier areas into more settled areas, most notably the mountainous region of Swat.