ISLAMABAD, Pakistan  A powerful Taliban faction in a northwestern tribal region has said it is withdrawing from a peace deal with the government to protest continuing strikes by American drones, confronting the Pakistani military with a possible two-front campaign against militants, according to Pakistani news reports on Tuesday.

The Taliban faction, led by Hafiz Gul Bahadur, operates in the mountainous North Waziristan area along the border with Afghanistan.

It struck a peace deal with the authorities in February 2008, but Mr. Gul Bahadur said the truce was no longer operative. The Taliban announcement on Monday came as American reinforcements were moving into Afghanistan. Taliban fighters there have traditionally relied on havens in Pakistan’s lawless tribal regions.

One day before the announcement, as many as 150 militants attacked a Pakistani military convoy about 22 miles west of Miramshah, the capital of North Waziristan. At least 30 soldiers  the Taliban claimed 60  were believed to have been killed in the ambush, which pointed to the army’s vulnerability in the area.