A U.S. commander said Tuesday he is "deeply ashamed" by the Marine killings of Afghan civilians in March and reported that the American military has made condolence payments to their families.

"Today we met with the families of those victims: 19 dead and 50 injured," said Col. John Nicholson, commander of the 3rd Brigade, 10th Mountain Division, deployed in eastern Afghanistan. "We made official apologies on the part of the U.S. government" and payments of about $2,000 for each death.

Speaking to Pentagon reporters by video conference from Afghanistan, Nicholson read the apology he said he made to the families.

"I stand before you today, deeply, deeply ashamed and terribly sorry that Americans have killed and wounded innocent Afghan people," the statement said.

"We are filled with grief and sadness at the death of any Afghan, but the death and wounding of innocent Afghans at the hand of Americans is a stain on our honor and on the memory of the many Americans who have died defending Afghanistan and the Afghan people," the statement said.

In the March 4 incident in Nangahar province, an explosives-rigged minivan crashed into a convoy of Marines that U.S. officials said also came under fire from gunmen. Injured Afghans said the Americans fired on civilian cars and pedestrians as they sped away.

A U.S. military commander later determined that the Marines used excessive force and referred the case for possible criminal inquiry. The Afghan Independent Human Rights Commission said the Marines violated international humanitarian law by using excessive force when they fired along a 10-mile stretch of road.

Accounts of the number of dead and wounded varied, with some as low as 10 or 12.

Nicholson said officials went to great lengths to trace down all who might have been injured along the crowded highway as well as those not from the immediate area but there on that day at a crowded bazar. The military asked the Afghan government to help determine how many people had legitimate claims.

"We defaulted to the higher number ... but feel confident that each of these people were in fact involved in the incident," he said.

Military killings of civilians have been eroding Afghan support for international forces and Afghan officials have repeatedly pleaded with the United States and NATO to take care during operations that might harm civilians.

A number of recent deaths have deepened ill will among Afghans, whose support for international forces and the shaky U.S.-backed government is waning.

Hundreds of angry protesters chanting "Death to Bush" demonstrated in eastern Afghanistan a week ago after six people — including a woman and a teenage girl — were reportedly killed when U.S.-led coalition and Afghan forces raided a suspected car bomb cell.

The protest was held on the same highway where a Marine convoy killed the civilians Nicholson talked about Tuesday.

Nicholson declined to say anything more about the incident Tuesday, saying only that it is under investigation.

"This was a terrible, terrible mistake," the statement to the families said. "And my nation grieves with you for your loss and suffering.

"We humbly and respectfully ask for your forgiveness," it ended.

An Associated Press tally earlier this year indicated that as of mid-March, about 40 civilian deaths in 2007 could be attributed to NATO or U.S. action, based on figures from military and Afghan officials. That was out of a total of 83 civilian deaths from combat counted by AP.

AP counted at least 95 Afghan civilians killed during assaults by NATO and the U.S.-led coalition in 2006. It tallied 512 total civilian combat deaths for the year.