U.S. forces continued a massive hunt Friday for a missing military team in the mountains of northeastern Afghanistan, three days after a Special Operations helicopter bringing troops to rescue the men crashed amid enemy fire, killing all 16 service members aboard.

A man claiming to speak for the Taliban militia called news organizations Friday to say that Taliban fighters had captured one of the men and killed seven others. But U.S. military officials said there was no evidence to support the claim. The missing team was made up of fewer than 10 soldiers, one officer in Washington said.

"All we have to date is that our guys are missing," said Lt. Col. Jerry O'Hara, a U.S. military spokesman here. "We don't have any positive proof that shows us they were injured, they were captured, or they are just in a hiding spot, waiting for our forces."

The incident in Konar province began Wednesday, when a small team of Special Operations forces were hiking through the region as part of Operation Red Wing, a mission against al Qaeda fighters, according to the military officer in Washington. The officer said none of the team members had been found, nor was it known whether any had been killed or captured.

"They could be hiding under a rock, waiting," the officer said. "There's an ongoing operation searching for them."

According to O'Hara, U.S. commanders last heard from the team on Tuesday afternoon after it started taking fire. The downed Chinook helicopter, a Special Operations aircraft, was one of at least two sent to extract the team, O'Hara said.

The Chinook appeared to have been hit by a rocket-propelled grenade as it approached its intended landing site, causing it to smash into a mountainside, Lt. Gen. James T. Conway, director of operations for the Joint Chiefs of Staff, told reporters Thursday.

He said the troops on board -- eight members of a Navy SEAL team and eight Army airmen -- appeared to have died in the crash. On Thursday, U.S. forces were finally able to reach the site and recover the bodies, but the ground team was not found in the area.

O'Hara said "all available assets" were being used to find the men, but that the search had been hampered by the steep, forested terrain and the possibility that "at any turn the search can turn into a fire fight if we encounter enemy forces."

Military officials said it was unclear who had fired on the helicopter. In addition to al Qaeda fighters, insurgents linked to the Taliban militia and Gulbuddin Hekmatyar, a fugitive former Afghan official, are also reportedly operating in the area.

The incident came as U.S. and Afghan forces face growing violence from insurgent groups that appear to be numerous, well-equipped and intent on undermining Afghanistan's modicum of stability after two decades of civil strife, foreign military occupation and religious repression.

At the same time, an increase in street crime, gang violence, kidnappings of foreign aid workers, murders of Afghans who support the U.S.-backed government and continued high levels of drug crop cultivation and trafficking have added to a sense of insecurity in the country. Afghan officials have been struggling to rebuild their country since the Taliban militia was ousted by a U.S.-led military campaign at the end of 2001.

International aid organizations have pulled out of large swathes of the country, and in the capital, many foreign workers are largely confined to their compounds and offices. The chill deepened after Clementina Cantoni, 32, an Italian working for the United Nations, was kidnapped in the capital May 16 and held for three weeks before officials negotiated her release.

After successfully holding a presidential election last October, officials have begun preparing for a parliamentary vote in September, but the pre-election atmosphere this time is tense. Ethnic rivalries, the continuing power of regional militia bosses, and widespread corruption have marred election preparations.

Among all of the country's problems, the most serious appears to be the re-emergence of armed guerrillas. In the past three months, there have been dozens of attacks and clashes in several provinces. More than 400 suspected insurgents have been killed, along with several hundred Afghan civilians and soldiers. The U.S. military has suffered 45 deaths, including the 16 killed in the helicopter crash.

Until recently, the guerrillas have mainly clashed with troops in remote, rugged areas near the border with Pakistan, which, according to Afghan officials, they use as a haven. But the insurgents are increasingly targeting Afghan civilians.

On Thursday armed fighters kidnapped and killed a group of tribal elders in central Uruzgan province, then sent a boy to offer to exchange the bodies for those of dead militiamen who had been killed Wednesday while attacking a police station.

In other recent incidents, an Afghan election worker was shot in the face; six anti-drug workers were killed while driving the body of a slain colleague to Kabul; a prominent moderate Islamic cleric was assassinated; and, a suicide bomber killed 20 people at the cleric's funeral.

Staff writers Bradley Graham and Pamela Constable in Washington contributed to this report.

U.S. troops set up a checkpoint in Konar province, near Pakistan.