U.S. aircraft bombarded a suspected insurgent compound in a mountainous area of northeastern Afghanistan where a military team has been missing since Tuesday, military officials said Saturday.

A purported spokesman for the ousted Islamic Taliban militia called news organizations and claimed that 25 civilians had died in the airstrike on the compound in Konar province, a rugged region near the Pakistani border.

Lt. Col. Jerry O'Hara, a U.S. military spokesman, said American troops were still assessing the impact of the Friday night bombing. However, he said that precision weapons had been used and that it was unlikely civilians were killed.

"We don't target civilians," he said. "We put a lot of effort into ensuring we minimize any type of collateral damage. . . . Our operations are intelligence-driven."

A Special Operations helicopter carrying U.S. troops to rescue the missing team crashed amid enemy fire Tuesday, killing all 16 people aboard. Late Friday, their bodies were flown from the U.S. air base in Bagram, north of Kabul, en route to Dover, Del., for identification, O'Hara said. He described throngs of soldiers lining the long road running through the base, saluting as vehicles passed carrying flag-draped containers to the airstrip.

"When there's a departure ceremony, everybody who is not actively involved in a mission comes out to show their respect," O'Hara said. "But this was much more emotional because you have many more that were lost in this incident."

Also on Saturday, guerrilla fighters in eastern Paktika province detonated a roadside bomb under a passing convoy of more than 20 vehicles carrying officials from the United Nations as well as Afghan leaders and security forces.

The attack killed as many as six Afghan policemen and soldiers, and wounded at least two others, including a local police chief, according to news services and the U.N. spokesman here, Adrian Edwards.

Other violence included a battle between Taliban and Afghan government forces in the central province of Uruzgan in which 18 insurgents were killed, according to news services. The militia members appeared to be part of the same group of fighters who kidnapped and killed a group of tribal elders Thursday.

In Kabul, U.S. military officials released 57 Afghans who had been held at a detention facility at Bagram air base for many months on suspicion of being armed Muslim extremists. They were taken to the office of a government program that reintegrates former Taliban members and released to the custody of tribal elders.

Since January, 220 detainees have been released from the U.S.-run prison at Bagram, and 142 more are slated to be released shortly, according to a U.S. military statement. In May, President Hamid Karzai called for all Afghan prisoners to be turned over to Afghan government custody in the wake of reports of past abuse by U.S. guards at Bagram and Guantanamo Bay, Cuba.

Several of the released men complained bitterly of being detained for several years without charge. "There was no beating or torturing, but they were disrespectful of our culture and we didn't have good food for a long time," Ghulam Mustafa, 21, told the Reuters news agency.

In Konar, a massive five-day hunt for the missing U.S. team continued without success Saturday, O'Hara said.

The purported Taliban spokesman, Abdul Latif Hakimi, told news agencies by telephone Friday that Taliban fighters had captured one of the missing men and killed seven of them. But U.S. military officials have said there was no evidence to support the claim.

The missing team was made up of fewer than 10 Special Operations troops and was participating in a mission against al Qaeda fighters, U.S. officials have said.

The Chinook helicopter sent to extract the team appeared to have been downed by a rocket-propelled grenade, military officials said.

The air attack on the compound Friday night was part of an ongoing military mission in the area, O'Hara said. "That operation was still ongoing all the while we were conducting search and recovery for our 16 that we lost, and while searching for the missing service members that haven't been accounted for," he said.

Edwards, the U.N. spokesman, said the team in Paktika was on its way to negotiate with tribes in the area about security matters. He said that after the roadside bombing, the group may have come under small-arms fire, and that Afghan security forces subsequently detained several men suspected of taking part in the attack. The U.S. military said it was not aware of any small-arms fire.

Edwards said the ambush was the latest in a string of attacks on military forces, government officials, aid workers and civilians by gunmen intent on disrupting parliamentary elections scheduled for September. The violence has contributed to a growing climate of pessimism and fear.

"The thinking of the United Nations is that there is a serious problem with security and that with the elections coming up we, like most people, want this addressed," said Edwards.