Seven people have died after a Nato Chinook helicopter crashed in Afghanistan, the alliance has said.
Five crew members and two military passengers were killed in the crash. US military officials said the dead crew members were Americans.
A Taleban spokesman said his group had shot down the aircraft, which came down in the southern province of Helmand.
Fighting between Nato and Taleban insurgents has escalated in recent weeks - particularly in the south.
The nationalities of the two military passengers are still unclear.
AFGHAN AIR CRASHES
5 May 2006-10 US soldiers die after their Chinook helicopter crashes east of Kabul
24 April 2006- Five die when US anti-drugs plane crashes in southern Afghanistan
11 November 2005 - Civilian cargo jet from Bagram crashes killing eight
25 September 2005 - Five US soldiers die in Chinook crash in Zabul province
16 August 2005 - 17 Spanish soldiers die when Cougar helicopter crashes near Herat
28 June 2005 - 16 US soldiers die in Chinook crash in Kunar province
6 April 2005 - 15 US soldiers and three civilian contractors die in helicopter crash in Ghazni province
The helicopter crashed at around 2100 (1630 GMT) in the Kajaki district of Helmand, Nato's International Security Assistance Force (Isaf) said in a statement.
A rescue patrol was ambushed by "enemy fighters" and forced to call for an air strike to access the crash site, Isaf said.
Incidents of helicopters being shot down are relatively rare in the country, says the BBC's Alastair Leithead in Afghanistan.
About 30,000 alliance troops and another 10,000 US-led ones have been battling to boost the authority of President Hamid Karzai.
Nato is investigating the cause of the crash.