Afghan girls walk past the graves of nine children killed in a US air strike, at a local cemetery in village Hutala (File Photo - Dec. 7, 2003)
U.S and Afghan officials say an investigation is underway into the killings of civilians during an ongoing counter-terrorism operation in the mountains of northeastern Afghanistan. Pentagon officials have confirmed the deaths of two Navy commandos whose unit's disappearance indirectly led to the civilian deaths.

Afghan officials say up to 17 civilians, including women and children, were killed in U.S air strikes last Friday against suspected rebel hideouts in the northeastern province of Kunar, which borders Pakistan.

Speaking to reporters in Kabul Tuesday, Presidential spokesman Jawed Ludin condemned the killing of the civilians, saying it had saddened President Hamid Karzai.

"We are now investigating to find exactly what happened, how many have suffered and what caused that suffering? We need to make sure that safeguarding lives of civilians remains our top most priority," he said.

The U.S military has said that coalition forces regret the loss of innocent lives, and are investigating the incident to prevent future occurrences.

The military says the targeted compound was a known operating base for terrorist attacks in the Afghan province. About a week ago, insurgents shot down a U.S transport helicopter in the same region, killing all 16 American servicemen on board.

The aircraft was trying to rescue a small team of U.S Navy SEALs that had disappeared in the mountainous region. The air strikes that led to the civilian deaths occurred during the search for the SEALs, the Navy's commando unit.

Pentagon officials are reported as saying two U.S soldiers from the missing team have been found dead. They say another has been rescued, while operations continue to recover the remaining team members.

Anti-government guerillas linked to the now-ousted Taleban regime have stepped up attacks in Afghanistan in an effort to undermine parliamentary elections scheduled for September. Much of the violence has taken place in the Afghanistan-Pakistan border regions.

Presidential spokesman Ludin, without naming any country, once again has suggested anti-government guerrillas are receiving foreign support.

"They actually come from somewhere," said Mr. Ludin. "They are being supplied by someone, and they are being led by someone. Those supply routes, those leaders and those sanctuaries are the ones that we need to focus on and we need to destroy."

U.S. and Afghan officials have in recent months alleged that Taleban insurgents have found sanctuaries in neighboring Pakistan, a charge the Pakistani government strongly rejects.