Six US soldiers killed in Afghan helicopter crash

Blackhawk crash kills 6 Americans in Afghanistan 2:53

KABUL - Six U.S. soldiers serving with the NATO International Security Assistance Force were killed when their Sikorsky UH-60 “Blackhawk” helicopter crashed in southern Afghanistan Tuesday, officials said.

According to U.S. military officials, two U.S. Army Blackhawk helicopters were flying in tandem over southern Afghanistan when one suddenly dropped from the sky and crashed.

The situation became desperate when the helicopter’s seven-man crew came under heavy enemy gunfire.

By the time a rescue team was deployed, six of the crew members had been killed, with only one surviving with serious injuries.

The cause of the crash is under investigation, NATO said in a statement. U.S. military officials said the probe will determine whether the chopper was brought down by mechanical failure or gunfire.

NATO did not disclose the nationalities of the victims but the U.S. official said they were American.

The helicopter crashed in the Shahjoi district of the Zabul province, according to its deputy governor Mohammad Jan Rasulyar. Taliban fighters remain a serious threat in the area.

Aircraft crashes are not uncommon in mountainous Afghanistan. In August 2011, 25 U.S. special operations forces were among 38 killed when the Taliban shot down a transport helicopter.

The six fatalities on Tuesday bring the total number of Americans killed in the 12-year war to 2,160.

About 43,000 American forces remain in Afghanistan, and about 80,000 total ISAF forces.

A pending security agreement with the Afghan government could drop the number of Americans to under 10,000 by the end of 2014. That agreement, however, would commit U.S. forces to another 10 years in Afghanistan.

NBC News' Jeff Black, Alastair Jamieson and Reuters, contributed to this report.