KABUL: A helicopter crash and a separate collision involving two other choppers killed 14 Americans yesterday in one of the deadliest days for US troops in the war in Afghanistan, the US military said.

In the first crash, a helicopter went down in the west of the country after leaving the scene of a firefight with insurgents, killing 10 Americans - seven troops and three Drug Enforcement Administration agents. The casualties are the first DEA deaths in Afghanistan since the drug agency began operations there in 2005. Eleven American troops, one US civilian and 14 Afghans were also injured.

In a separate incident in the south, two other US choppers collided while in flight, killing four American troops and wounding two more, the military said.