The shooting occurred early yesterday, the morning after armed men and soldiers exchan-ged fire at a military compound in the region. Pakistani forces have been carrying out a sweep for terrorist suspects, and tension is high in the area.

The minibus failed to stop at a roadblock in Zeri Noor, a village just outside of Wana, the main town in tribal South Waziristan, army spokesman Gen. Shaukat Sultan told AP. He said soldiers only shot at the bus after someone inside opened fire on them.

"It was a terrorist act," he said.

Allah Dad, a local resident, told AP that the bus was filled mostly with Afghan refugees on their way to the border. A taxi driving near the minibus was also hit, and the driver killed, Dad said.

He said as many as 12 people were killed, and seven more injured in the incident.

"They opened fire when the bus didn't stop," Dad said. "There is a lot of tension in the area and a lot of troops. The roads to Afghanistan have been sealed."

Two local officials who spoke to the AP earlier on condition of anonymity did not mention an exchange of fire, saying it was not clear exactly what prompted the shooting.

The deaths are sure to increase anger in the region. Tribal leaders deeply resent the presence of the army on their lands. Pakistani forces have been slowly increasing their presence under pressure from Washington to crack down on al-Qaeda and Taliban suspects, who are believed sheltering in the region.

In the operation Tuesday in Wana, troops arrested 25 suspected terrorists, none of whom have been identified.

In Friday's raid, armed men tried to sneak into a military compound in Wana, sparking a shootout, Sultan said Saturday. There were no casualties and the spokesman said he had no details.

"I can only say that there was an exchange of fire but there were no casualties," Sultan told The Associated Press.

Wana is located about 190 miles west of the capital, Islamabad.