KABUL, June 30 -- U.S. forces have recovered the bodies of 16 American troops in the wreckage of a U.S. special forces helicopter that crashed into a rugged mountain ravine in eastern Afghanistan, the Pentagon said Thursday.

"At this point, we have recovered all 16 bodies of those servicemen who were on board the MH-47 helicopter that crashed on Tuesday," Marine Corps Lt. Gen. James Conway, director of operations for the U.S. military's Joint Staff, told a Pentagon briefing. "Positive identification and family notification are under way and expected to be completed soon."

Earlier reports said 17 American troops were on board the helicopter.

U.S. ground troops braved gunfire, stormy weather and the rough terrain of Konar province near the Pakistani border to reach the site. They were supported by bombardment from attack aircraft.

The downed helicopter, a Special Operations variant of the CH-47 Chinook, was carrying a team of Navy SEALs to be implanted in the combat zone, according to a senior defense official in Washington.

Troops on a second helicopter nearby reported Tuesday that the craft was likely brought down by ground fire. Other military officials said it might have been downed by a grenade or crashed while evading fire as it approached a landing zone. It went down in a rugged area about 10,000 feet in elevation, officials said.

Further hampering the rescue effort was the loss of a Predator drone that had provided imagery of the crash area Wednesday, according to the senior official. That aircraft might also have been shot down, the official said.

Marine Gen. Peter Pace, vice chairman of the Joint Chiefs of Staff, told a Senate committee Wednesday that the incident appeared "to be a shootdown of one of our Special Operations helicopters," probably by a rocket-propelled grenade. "Our hearts go out to their families," Pace said.

The incident followed a three-month escalation of armed clashes that have killed between 240 and 465 suspected anti-government fighters, 29 U.S. troops, 43 Afghan police officers and soldiers, and 125 civilians.

Taliban and al Qaeda forces were once believed to have been reduced to a marginal force in the country, and a peaceful presidential election was held in October. Since then, however, insurgents have stepped up attacks, apparently hoping to sabotage parliamentary elections scheduled for September.

U.S. officials said it was not clear if the insurgent forces in the crash were from the revived Taliban militia or included foreigners. A Taliban spokesman has asserted responsibility for the attack. Afghan officials have repeatedly complained of fighters slipping into the country from Pakistan.

U.S. military officials would not comment on the number of forces involved, but they said the helicopter was shuttling troops into the area as part of Operation Red Wing, a sweep aimed at capturing or killing al Qaeda militiamen.

The governor of Konar, Asadullah Wafa, said the area has been a haven for al Qaeda members. Fighters linked to the Taliban, as well as loyalists of Gulbuddin Hekmatyar, a former minister who is now a fugitive opponent of the U.S.-backed government in Kabul, are also reportedly operating in the territory.

Wafa said fighters rarely stayed overnight in the harsh terrain where the fighting took place. "They come in to attack, and then they rush back into Pakistan," he said. In recent weeks, he added, militia attacks have killed as many as 15 people.

The U.S. operation in Konar is part of a larger spring campaign by U.S. and Afghan forces to flush out fighters from hideouts in the east and south of Afghanistan. Despite heavy losses, the militiamen have shown themselves to be hardy, well-equipped fighters who can wage battles for hours. There are about 18,000 U.S. troops in the country.

Fred Barbash reported from Washington. Staff writer Bradley Graham in Washington contributed to this report.