A roadside bomb killed as many as 14 Pakistani soldiers in the northern border region of North Waziristan on Sunday, military officials said, a day after the Pakistani Taliban leader called for attacks on the military in the area to stop.
The explosion occurred on a road about 50 km (30 miles) south of the provincial capital of Miranshah. Twenty-one soldiers were wounded in the attack, senior army officials said.
A spokesman for the Mujahideen Ansar, a group dominated by Uzbek fighters, claimed responsibility and told Reuters the attack was retaliation for the Pakistani army's complicity in drone strikes. The group is allied to Pakistan Taliban fighters.
Pakistan frequently protest publicly about U.S. drone strikes but has not taken any legal steps to end them.
On Saturday, Hakimullah Mehsud, the leader of the Tehrik-e-Taliban Pakistan (TTP), had circulated a leaflet calling for an end to the Taliban's infrequent attacks on Pakistani soldiers in North Waziristan.
Thousands of Pakistani soldiers are stationed in North Waziristan.
The ceasefire did not apply to the rest of the country, where there are often fierce clashes between the Taliban and security services.
The mountainous tribal region of North Waziristan along the Afghan border is a key stronghold of the Taliban and al-Qaeda. South Waziristan is under the control of the Wazir tribe, who have a peace deal with the Pakistani military.
It was unclear if the leaflet was related to rumors of splits in the movement. It called on local and foreign fighters to unite because "the enemy is trying to divide and rule us".
The Taliban have formed alliances with a number of other militant groups in North Waziristan who are violently opposed to the Pakistani state.
Some Taliban commanders are divided over whether the Pakistani state or NATO forces are their top target.
Those divisions were laid bare in November by an attempted suicide attack on Mullah Nazir, a top militant commander from the Wazir tribe in South Waziristan. He had signed a peace deal with the Pakistani army but supported attacks on NATO forces in Afghanistan.
The attack was widely believed to be the work of rival Taliban commanders, and the Wazir tribe ordered Hakimullah Mehsud's tribe out of their lands.
Mullah Nazir was killed in a drone strike this month and it is unclear if his successor will continue his policies, or what relationship the Wazir tribe will have with the Mehsud tribe.
Pakistani army officials have also told Reuters that there are tensions between Mehsud and his deputy. The two men recently appeared together in a video to deny the allegations.
The decision to halt attacks against the Pakistani army in North Waziristan could signal the Pakistani Taliban's intention to help the Afghan Taliban fight U.S.-led NATO forces in the neighboring country, or focus more closely on attacking Western targets inside Pakistan.
Or it could be more specifically aimed at unifying local factions. Mehsud's statement specifically addressed both foreign fighters and local Taliban.