Kabul: Six US troops from the NATO mission in Afghanistan were killed and one was wounded in a helicopter crash on Tuesday, with officials saying it was not a suspected Taliban strike.
The Afghan insurgents, however, immediately claimed responsibility for the deaths, using their main Twitter account to report that their fighters had shot down the US chopper in the southern province of Zabul.
The incident was the single biggest loss of life for the NATO mission in Afghanistan since seven Georgian soldiers died when a suicide bomber blew up a truck loaded with explosives outside a base in Helmand province in June.
"Six International Security Assistance Force (ISAF) service members died following an aircraft crash in southern Afghanistan today," an ISAF statement said.
"The cause of the crash is under investigation, however initial reporting indicates there was no enemy activity in the area at the time of the crash."
Defence officials in Washington told AFP that the fatalities were US troops riding in a UH-60 Blackhawk aircraft.
"I can confirm six Americans were killed," said one official, who spoke on condition of anonymity.
An investigation was underway to determine "the cause of engine failure," the official said.
Although there was no insurgent fire on the aircraft before the Blackhawk crashed, "once it was down, there was enemy fire," said a US military officer, who asked not to be named.
The Taliban Twitter account, under the name Abdulqahar Balkhi, said the helicopter was brought down today afternoon while flying low over the district of Shah Joy in Zabul.
"(The) chopper crashed in (a) ball of flame... Killing all 8 invaders aboard," the account said.
The Taliban regularly make unsubstantiated claims of attacks on NATO and Afghan forces and also exaggerate casualty numbers in proven strikes.
Provincial officials confirmed the incident in Zabul, a restive province bordering on Helmand and neighbouring Pakistan.