NATO and Afghan authorities were investigating Saturday whether an airstrike during the intensive search for two missing U.S. paratroopers mistakenly killed eight Afghans and wounded more than 20 Afghan and American forces.

NATO said the deaths came during an hourslong fight Friday between members of a joint search operation and insurgents in western Afghanistan. Four Afghan soldiers, three policemen and a civilian interpreter died. Five U.S. and 15 Afghan soldiers, as well as two police officers and another civilian interpreter, were wounded, the alliance said.

Afghanistan's Defense Ministry said the soldiers and police were killed at a joint base "during an air attack by NATO forces in Badghis province," where the paratroopers disappeared. The alliance could not confirm whether the base had been hit.

"We are saddened by the loss of life and injuries sustained during this very important mission," U.S. Navy Capt. Jane Campbell, spokeswoman for the NATO forces, said in a statement.

The two U.S. paratroopers disappeared Wednesday while trying to recover airdropped supplies from a river. Officials indicated it was unlikely the two from the 4th Brigade Combat Team, 82nd Airborne Division, had been taken captive. Western regional police Chief Gen. Ikram Uddin Yawar said on Friday that the two had been swept away by the current in the Bala Murghab district. The search was continuing Saturday.

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

Separately, the deputy governor of the southern province of Zabul, Ali Khail, said NATO forces raided an Afghan Red Crescent office in the city of Qalat early Saturday, killing a security guard and arresting three local Red Crescent employees.

NATO issued a statement saying coalition forces killed a militant and arrested a few suspected militants, including someone who was helping insurgents transport weapons and bomb-making materials to the area.

Red Crescent spokesman Walid Akbar confirmed that international forces had raided the office, but said he had not received any reports of deaths.

Akbar said his organization was negotiating with provincial authorities for the release of the three arrested men, whom he identified as a driver, a communications officer and a guest.

"We are a neutral organization. We help both parties. We help the victims of the war," he said.

According to the NATO statement, alliance forces and Afghan police had targeted the compound, "which credible intelligence reported as a location known historically to be used by Taliban commanders."

It said the joint forces came under fire from inside the compound when the police chief in the operation called for those inside to come out. One man was killed when the forces returned fire, it said.

One of those arrested identified himself as a Taliban ally, the statement said, adding that he was responsible for financial support and transporting bomb material and weapons into the area.