A NATO helicopter crashed in eastern Afghanistan on Tuesday killing two US troops, officials said, adding there was no insurgent activity in the area at the time of the incident.
Taliban militants said they had shot down the helicopter, but the group often makes exaggerated claims of success on the battlefield against NATO forces and the US-backed government.
"Two International Security Assistance Force service members died following a helicopter crash in eastern Afghanistan today," ISAF said in a statement.
"The cause of the incident is under investigation, however initial reporting indicates there was no enemy activity in the area at the time of the crash."
Witnesses told AFP the accident happened in Nangarhar province bordering Pakistan, with the helicopter crashing into farmland in the district of Pachir Wa Agam.
A Taliban spokesman said a specially-trained group of militants had shot down the helicopter.
Helicopter crashes are fairly frequent in Afghanistan, where the 100,000-strong international mission relies heavily on air transport as it battles the insurgency across the south and east of the country.
Last month five US troops were killed in a crash in the southern province of Kandahar when their Black Hawk helicopter came down during a heavy rainstorm.