NATO would not comment on whether an airstrike had taken place.

Defense Ministry spokesman Gen. Mohammad Zahir Azimi said an Afghan army commando unit, district police members and foreign forces were in the base in the Bala Marghab district at the time of the airstrike Friday afternoon.

Roauf Ahmadi, a spokesman for the western regional police commander, said the airstrike also wounded 15 Afghan soldiers and one policeman.

"During an air attack by NATO forces in Badghis province, seven Afghan forces were killed," the Defense Ministry said in a statement.

The ministry said NATO and Afghan authorities were investigating the incident and would issue a report soon.

On Friday, NATO headquarters in Kabul said more than 25 NATO and Afghan security forces members were injured during a search for two U.S. paratroopers missing from a resupply mission since Wednesday.

Lt. Col. Todd Breasseale, a NATO spokesman, said Friday that initial reports indicated they had been wounded due to insurgent activity.

Officials indicated that it was unlikely the two missing personnel from the 4th Brigade Combat Team, 82nd Airborne Division, had been taken captive.

Local police said the two Americans were swept away by a river in the western province of Badghis when they tried to retrieve supplies that had been airlifted and had accidentally fallen into the water.