An American soldier wounded two days ago in eastern Afghanistan was shot by a Pakistani border guard who had been ordered by a U.S. patrol to return to Pakistan, the U.S. military said Tuesday.

The American soldier was grazed in the head by a bullet on Sunday at Shkhin, a small town on the Pakistan border where U.S. forces have a base.

The wounded American, whose name has not yet been released, was "a member of a patrol assisting a Pakistan unit on a routine mission," the U.S. military said in a statement at Bagram Air Base.

"A Pakistani border scout opened fire with a G3 rifle after the U.S. patrol asked him to return to the Pakistan side of the border," the statement said.

"That individual and several others retreated to a nearby structure. Close air support was requested and one 500-pound bomb was dropped on the target area," the statement said.

It was unclear why the Pakistani border guard opened fire.

Residents in a the area near the Afghan border said Monday that bombs dropped by U.S. planes operating in Afghanistan fell near an abandoned religious school in Pakistan and a police checkpoint, but no injuries were reported.

U.S. warplanes were seen operating in the extreme western portion of Afghanistan where remnants of the al-Qaida terror network and the former Taliban regime are believed to be hiding to mount attacks on U.S. troops.

It wasn't immediately clear whether the bombs seen by the local residents were the same ones.

One bomb hit a perimeter wall at an abandoned madrassa, or Islamic school, in the village of Burmol, resident Allah Noor Khan said by telephone from Burmol, about 200 miles southwest of Peshawar in Pakistan's South Waziristan district.

Soon after the shooting Sunday, the American soldier was flown to a military medical center at Landstuhl, Germany and is reported in stable condition there.

Earlier this month a paratrooper from the U.S. Army's 82nd Airborne Division, Sgt. Steven Checo, 22, was shot and killed while on a nighttime operation near Shkhin, which is in the eastern province of Paktika, near the border of Pakistan.

The assailants fled into Pakistan.