KABUL, Afghanistan - Aerial bombing of a valley in western Afghanistan several days ago by the American military killed at least 42 civilians, including women and children, and wounded 50 more, an Afghan government investigation found Wednesday. A provincial council member who visited the site independently put the figure at 50 civilians killed.

President Hamid Karzai said at a news conference in Kabul that the Afghan people could no longer tolerate such casualties. "Five years on, it is very difficult for us to continue accepting civilian casualties," he said. "It is becoming heavy for us; it is not understandable anymore."

There have been several episodes recently in which civilians have been killed and foreign forces have been accused of indiscriminate or excessive force. That has prompted Afghan officials to warn that the good will of the Afghan people toward the government and the foreign military presence is wearing thin.

The government delegation reported that three villages were bombed last week in the Zerkoh Valley, 30 miles south of the western city of Herat, and 100 houses were destroyed and 1,600 people were now homeless, Farzana Ahmadi, a spokeswoman for the governor of Herat Province, said by telephone.

"The report says that some women and children were drowned in the river, and it was maybe in the heat of the moment that the children and people wanted to escape and jumped into the water," she said. "This all happened just because of a lack of coordination between international forces and our forces."

A provincial council member from Herat, Naik Muhammad Eshaq, who went to the area independently, said he had visited the three bombing sites and produced a list of 50 people who had died, including infants and other children under age 10. People were still digging bodies out of the rubble of their mud-walled homes on Tuesday afternoon, he said.

American Special Operations forces conducted raids in the area on Friday and Sunday, and on both occasions they called in airstrikes when they encountered armed resistance, the military said. It said in a statement that it had killed 136 Taliban fighters, including some who were trying to flee across the river.

In Washington, a Pentagon spokesman, Lt. Col. Jeremy Martin, said, "We're aware of the allegations, but we don't have any information through operational channels to confirm the latest incident." He added, "We take all measures possible to limit civilian casualties."

Villagers held protests over the bombing in the nearby district town of Shindand on Monday and set fire to government offices.

Ms. Ahmadi, the Herat spokeswoman, said all 42 dead counted by the government delegation were civilians. She said the government was continuing its investigation to see if enemy fighters had also been killed.

Mr. Eshaq, the council member, said villagers were adamant that there had been no Taliban fighters in the area. "I could not find any military men," he said.

Mr. Karzai accused American and NATO forces of failing to coordinate with the Afghan authorities.

"I have worked personally in the past four years, almost on a monthly and weekly basis, with the international community to bring some sort of coordination and cooperation to such raids on homes and on villages," he said. "Unfortunately that cooperation and coordination, as we tried it, has not given us the results that we want, so we are not happy about that and we can no longer accept the civilian casualties the way they are occurring.

"We are very sorry when the international coalition force and NATO soldiers lose their lives or are injured," he said. "It pains us. But Afghans are human beings, too."

Abdul Waheed Wafa reported from Kabul, and Carlotta Gall from Islamabad, Pakistan. David S. Cloud contributed reporting from Washington.

Copyright 2007 The New York Times Company