Two helicopters collided Monday in southern Afghanistan

Two helicopters collided Monday in southern Afghanistan, killing four American troops and injuring two, the military said.A third U.S. helicopter crashed in a separate incident in the west, leaving "some dead," U.S. military spokeswoman Elizabeth Mathias said. She did not have details on how many or their nationalities.

It was unclear what caused the collision in the south. U.S. military spokesman Col. Wayne Shanks said the military had ruled out hostile fire but he did not have any other details. He said the injured had been evacuated to hospitals inside Afghanistan.

The third helicopter went down during an operation by Afghan and international forces in which a dozen militants were killed, the military said. It said the crash happened in western Afghanistan without giving a more precise location.

Mathias said hostile fire or other insurgent activity was not believed to be the cause, but they were still looking into all possibilities. Troops from the U.S., other NATO countries and Afghanistan were on board the helicopter, she said, adding that a recovery operation was under way.

Taliban spokesman Qari Yusuf Ahmedi claimed Taliban forces shot down the helicopter in Badghis province's Darabam district. Badghis is in the northwest of the country. It was impossible to verify the claim.This has been the deadliest year for international and U.S. forces since the 2001 invasion to oust the Taliban. Fighting spiked around the presidential vote in August, and 51 U.S. soldiers died that month — the deadliest for American forces in the eight-year war.

More than 30 American troops have died so far in October.The deaths come as U.S. officials debate whether to send tens of thousands more troops to the country and the Afghan government scrambles to organize a Nov. 7 runoff election between President Hamid Karzai and his top challenger from an August vote that was sullied by massive ballot-rigging.

Posted in: Afghanistan,Fighting Al Qaeda and Taliban,Helicopter