Updated

The U.S. coalition blamed Taliban militants Saturday for causing what Afghan officials say are dozens of civilian deaths during a prolonged battle that included American airstrikes. The U.S. said an unspecified number of civilians died but did not take responsibility for any deaths.

Afghanistan's Interior Ministry declined to endorse the U.S. report, saying its own investigation would be completed soon.

Afghan officials have estimated up to 147 people died in the battle in the western province of Farah on Monday, but a U.S. spokeswoman called that number exaggerated. The U.S. report did not offer an estimate of the number killed in the battle.

The preliminary report said Taliban fighters herded Afghan villagers into houses to use as human shields while they fired on coalition forces in two villages in Farah. The report said that U.S. forces had responded to a call for help from Afghan forces and that militants attacked the troops from several locations.

Troops called for airstrikes on the militant positions, and a U.S. spokeswoman said Saturday that fighter aircraft made 13 passes over the two villages, using a combination of flares, strafing runs and bombs.

"The investigation suggests that villagers had taken refuge in a number of houses in each village. Reports also indicate that Taliban fighters deliberately forced villagers into houses from which they then attacked ANSF (Afghan security forces) and Coalition forces," a statement from the U.S. coalition said.

Neither the U.S. nor Afghan forces took responsibility for killing civilians in Saturday's statement. A second U.S. statement said villagers seeking medical treatment told Afghan doctors that militants were fighting from rooftops while forcing the villagers to remain in their compound.

"The joint investigation team strongly condemns the brutality of the Taliban extremists deliberately targeting Afghan civilians and using them as human shields," the statement said.

Other groups expressed concern for the investigative process. Human Rights Watch on Saturday blasted the U.S. military and said the attack was likely to be "the largest and most tragic loss of life to U.S. bombs so far in Afghanistan."

"Yet another devastating error inevitably calls into question the continued viability of the use of U.S. and NATO airpower in Afghanistan," said Rachel Reid, the group's Afghanistan researcher. "The procedures for protecting civilians and verifying intelligence before launching attacks are clearly not working and must be thoroughly reviewed again."

At the U.N. headquarters in Kabul, an official said that some at the world body were uneasy that the "very same people who are accused of causing the civilian casualties are being sent back to investigate." The official -- who spoke on condition of anonymity because he wasn't authorized to share such internal views -- called for an independent investigation.

The U.S. said the findings came from a joint U.S.-Afghan investigation. But the country's Interior Ministry and Farah's police chief both said that their delegations were continuing to investigate and that they did not endorse the U.S. report.

"In that statement, they didn't mention either the Ministry of Interior or the Ministry of Defense," said Zemeri Bashary, the Interior spokesman. "Our teams are still in Farah collecting data. We will come out with our results soon."

The U.S. statement did not say how many people died in the battle. American officials have indicated they may never put out a number because those killed in the battle had been buried by the time investigators arrived.

"We're hoping to provide additional detail," said Lt. Cmdr. Christine Sidenstricker, a U.S. spokeswoman, who said that fighter aircraft made 13 passes during the battle. "The issue we've got right now is that we're still trying to get good numbers, and we're still trying to coordinate between the teams that went out and make sure we have accurate information."

Abdul Basir Khan, a member of Farah's provincial council, said Friday that he had collected the names of 147 people killed in the fighting. Other Afghan officials have said dozens of civilians died in the battle, ranging from 70 to more than 100. A U.S. spokeswoman has called such reports "extremely over-exaggerated."

The U.S.-Afghan team of investigators visited the villages this week and saw two mass graves and one burial site with seven individual graves, the joint U.S.-Afghan statement said.

"The joint investigation team confirms that a number of civilians were killed in the course of the fighting but is unable to determine with certainty which of those casualties were Taliban fighters and which were noncombatants because those killed are all buried," the statement said.

Civilian casualties have long been a source of tension between the U.S. and Afghan President Hamid Karzai, who has pleaded with American officials to cut down on the number of civilians killed in its military operations.

Karzai on Friday, during a visit to the U.S., said: "We cannot justify in any manner, for whatever number of Taliban, for whatever number of significantly important terrorists, the accidental or otherwise loss of civilians."