ISLAMABAD - Assailants threw a bomb at a police checkpoint in eastern Pakistan before dawn Saturday, killing seven officers, police said.
District Police Chief Malik Tassadaq Hayyat said the attack came near the town of Mianwali in eastern Punjab province. He said residents also heard gunfire before the explosion that knocked down the roadside checkpoint.
Hayyat would not say who could be behind the attack but said it was "an act of terrorism" and officers were still investigating.
Mianwali lies at the edge of Pakistan's troubled North West Frontier Province, where police and troops have been fighting pro-Taliban militants since soon after the Sept. 11, 2001 attacks in the United States.
Meanwhile, suspected militants attacked a terminal used for supplies to NATO in Afghanistan and burned at least two vehicles, police said Saturday.
No one claimed responsibility for the late Friday attack on the terminal in the northwestern city of Peshawar. Police official Attique Shah said they had stepped up security.
The two attacks came hours after authorities said security forces backed by helicopter gunships had killed 52 militants in two raids in northwestern Pakistan, a lawless region where the Taliban and al-Qaida increasingly hold sway.
The raids took place Friday near the Khyber region, said Fazal Mahmood, the No. 2 government representative in the area. They destroyed five militant hide-outs, a large ammunition depot and eight vehicles, he said.
It was not possible to independently verify his account because the region is dangerous to visit.
Militants have stepped up attacks in the Khyber region in recent months, seeking to disrupt a vital supply line for Western forces in neighboring Afghanistan.
Suspected militants bombed a bridge on Tuesday, cutting the supply line, and a suicide car bomber blew himself up Friday in the troubled region, wounding six people including two policemen.
Government official Bakhtiar Khan said the repaired bridge reopened Friday for all traffic, including trailer trucks supplying NATO and U.S. forces.
Pakistani officials worry that rising militancy is fanning tension between the country's Sunni Muslim majority and Shiite minority. The Taliban and several other violent extremist groups are Sunnis.
