Twenty soldiers were killed when a bomb explosion hit a vehicle in North West Pakistan on Sunday, military officials told NBC News.
A military official in Bannu, where the attack occurred about 8:45 a.m. local time, said the dead were Pakistan army troops and personnel from the paramilitary Frontier Corps.
More than two dozen others were injured, officials said. The military official feared that death toll could rise because some of the injured were in critical condition. He said some were airlifted to the military hospital in Peshawar.
Officials said a military convoy was carrying troops from Bannu to the Razmak area in North Waziristan when the explosion occurred.
Two officials said the bomb may have been planted in the vehicle, but another said a suicide bomber may have struck.
They said the vehicle had been hired from a civilian vendor because of a shortage of military vehicles.
The Pakistani Taliban claimed responsibility for the attack, a spokesman for the group said.