About 100 insurgents raided a government center Sunday near the border with Pakistan, and more than two dozen of the attackers were killed in the battle, authorities said. Two policemen also died.

American troops and aircraft assisted Afghan forces during the battle in Spera district of eastern Khost province, said provincial governor Arsallah Jamal.

The militants attacked the police guarding the district center from four directions before being pushed back, Jamal said. More than 50 militants died, while the rest fled into Pakistan, he said. Two policemen died and four were wounded.

The troops "called for air strikes consisting of heavy machine gun fire from helicopters," NATO said in a statement.

"Some insurgents attempted to take cover in a nearby building that helicopters then struck with missiles," the statement said. "The number of insurgents killed is in double-digit figures.

"Also in Khost, a suicide bomber targeting a road construction crew killed one person and wounded four others Sunday, deputy provincial police chief Yaqoub Khan said. All the victims were road workers, Khan said.

Separately, several militants were killed and four were detained during an operation in neighboring Paktia province on Saturday, the U.S.-led coalition said.

The troops were searching compounds when a group of insurgents fired on them from a fortified position, the statement said. "Coalition forces responded with small-arms fire, killing the militants," it said.

Afghanistan faces intensifying militancy nearly seven years after a U.S.-led invasion ousted the hard-line Islamic Taliban movement from power.

The number of militant attacks in eastern Afghanistan has increased by 40 percent over the same period last year.

Afghan and Western officials say Pakistan has not done enough to crack down on militant hideouts on its side of the border, a charge Pakistan rebuffs.

More than 2,700 people — most of them militants — have died in insurgency-related violence this year, according to an Associated Press tally of official figures.