KABUL, Afghanistan — The Afghan Defense Ministry and local officials in Badghis Province said on Saturday that seven members of the Afghan security forces had been killed in a NATO airstrike the day before that was part of an effort to aid a beleaguered Afghan and NATO operation against the Taliban.

A NATO spokesman confirmed that the seven Afghan officers had been killed, as well as an Afghan civilian working with the Afghan forces. The North Atlantic Treaty Organization is investigating whether its close air support was responsible for the casualties. According to NATO, five American soldiers were wounded in the operation against the militants, along with 15 Afghan soldiers, two Afghan police officers and one Afghan civilian working with the troops.

If NATO close air support is responsible for the casualties, it would be one of the worst cases of friendly fire in the course of the eight-year war.

The troops were in rural Badghis Province in the country’s far northwest, in a relatively flat area, traversed by the Morghab River. They were searching for two American soldiers who had been missing since Wednesday. The Americans had vanished while on a resupply mission.

Local officials in Badghis Province said the two soldiers, who are paratroopers from the Fourth Brigade Combat Team, 82nd Airborne Division, had gone to pick up food supplies from an airdrop.

There are conflicting stories about what happened to them. Some local people said that the supplies were dropped inadvertently into the river and that as the men tried to retrieve them they were swept away in the swift current. But Maulvi Ghulam Farouk, a Taliban leader in the Bala Murghab district of Badghis Province who was present during the fighting, said that the soldiers fought with the Taliban and that the Taliban had killed one of them. However, he said, a couple of the Taliban were wounded during the fight and retreated.

On both Thursday and Friday, the joint NATO and Afghan force arrived to search for the missing soldiers. On Friday, the Taliban attacked the joint force and a fierce fight ensued.

“On Friday, they came with Afghan forces, looking again for their dead soldiers. It was afternoon when they came, and there was fighting for half an hour or maybe even one hour,” said Mr. Farouk, the Taliban commander.

“Then the aircraft came,” he continued. “And when the aircraft came, we Taliban dispersed and they bombed where the Afghans and their NATO soldiers had been fighting. There were many casualties.”

Another Taliban spokesman, Qari Yousuf Ahmadi, said that during the fighting three Taliban were killed and five were wounded.

The Bala Murghab district governor, Mohammed Amin Achik, also confirmed the NATO bombing. “Yesterday there was a clash between the Taliban and the government; there are casualties among the Afghan security forces. I do confirm there was bombardment yesterday at the site of the fighting,” he said on Saturday.

“We are saddened by the loss of life and injuries sustained during this very important mission,” said Capt. Jane Campbell of the United States Navy, a spokeswoman for the international forces.

A legislator from Badghis Province, Senator Mohtrama Habibi, said she was upset at the NATO bombing. “If NATO really wanted to help, they should go and bombard the Taliban hideouts and sanctuaries,” she said.

“Once again, I request that they not to shed our youths’ blood,” Senator Habibi continued. “Those who were killed yesterday in the bombardment were poor police who were working with the government for only 5,000 Afghanis a month for their salary. They are those who had no choice to go to Iran or to work in another job.”

A monthly salary of 5,000 Afghanis would be about $100.

There is no indication from NATO, the Taliban or local authorities that the bodies of the missing soldiers have been found. Initially, a story circulated that villagers had located the bodies, Mr. Achik said. Now that report is in doubt, and NATO troops are still searching for the soldiers, he said.

The Taliban commander who was there during the fight denied that the Taliban had the bodies. “The dead bodies are not with us,” he said. “We think they are with the local people. We don’t know who took their bodies out of the water or where. The river is very long.”