Pakistan authorities say gunmen have opened fire on a bus carrying Shi'ite Muslim pilgrims in the country's southwest, killing 26 pilgrims.

Tuesday's attack took place in the Mastung district of Baluchistan province, about 50 kilometers from the provincial capital Quetta. The bus was on its way to Iran.

The bus driver told reporters that at least eight attackers carrying rocket launchers and Kalashnikovs stopped the bus and forced the passengers off. The gunmen then opened fire, killing more than two dozen Shi'ite pilgrims and wounding six others.

The driver said roughly 40 people were on the bus and some managed to escape the attack. He said no security had been provided for the Shi'ite pilgrims.

Television footage showed bodies being loaded onto ambulances. Victims' shoes were scattered on the ground.

Pakistan has a history of sectarian violence. The country has a Sunni Muslim majority, and although most Sunnis and Shi'ites coexist peacefully, extremists often target members of each community.

In other violence, Taliban gunmen attacked a Pakistani military checkpoint in the country's northwestern tribal belt, leaving at least 19 people dead.

Officials said the militants launched the attack in the Dabori region of Orakzai tribal agency, killing at least one soldier and wounding five others.

Security forces were able to kill more than 18 militants in the ensuing gunbattle. Pakistani helicopter gunships also were involved in the fight.

There was no independent confirmation of the death toll. The area is largely shut off from journalists and aid workers.

Last year, the Pakistani military launched an operation against the Taliban in Orakzai. Pakistan's semi-autonomous and remote tribal region near the Afghan border has been the center of militant activity. Domestic and Afghan Taliban elements are located there as well as al-Qaida operatives and other foreign fighters.