U.S. Chopper Down In Afghanistan

(CBS/AP)  The fate of more than a dozen U.S. troops is unclear after a U.S. CH-47 Chinook transport helicopter crashed Tuesday while ferrying reinforcements for counterterrorism operations in eastern Afghanistan, the military said.

Sources tell CBS National Security Correspondent David Martin that there were 16 troops on board. Although the military says the fate of those on board the helicopter, which crashed near Asadabad in Kunar province, is not immediately known, Martin reports that a heavy death toll is possible.

The wreckage is in a rugged area, so it could be difficult for rescuers to reach. It appears, Martin reports, that the Chinook hit a mountaintop, then rolled down a ravine.

The Taliban claimed responsibility in a phone call to The Associated Press.

Other helicopters and fixed-wing aircraft were deployed to the site, the military said. U.S. military spokesman Lt. Col. Jerry O'Hara had no other details.

Provincial Gov. Asadullah Wafa told The Associated Press that the Taliban downed the aircraft with a rocket. He gave no other details.

Purported Taliban spokesman Mullah Latif Hakimi called the AP before news of the crash was released and claimed that the rebels shot the helicopter down.

Hakimi often calls news organizations to claim responsibility for attacks on behalf of the Taliban. His information has sometimes proven untrue or exaggerated, and his exact tie to the group's leadership is unclear.

The crash was the second of a Chinook helicopter in Afghanistan this year. On April 6, 15 U.S. service members and three American civilians were killed when their chopper went down in a sandstorm while returning to the main U.S. base at Bagram.

The U.S. military has launched operations in several areas along the border with Pakistan. Those offensives target remnants of al Qaeda and the hard-line Taliban movement, as well as foreign fighters using high mountain passes to cross over from Pakistan.

Tuesday's crash comes after three months of unprecedented fighting that has killed about 465 suspected insurgents, 29 U.S. troops, 43 Afghan police and soldiers, and 125 civilians.

The violence has left much of Afghanistan off-limits to aid workers and has reinforced concerns that the war here is escalating into a conflict on the scale of that in Iraq.

Afghan and U.S. officials have predicted that the situation will deteriorate in the lead-up to legislative elections in September — the next key step toward democracy after a quarter-century of war.