WASHINGTON: The White House offered prayers on Thursday for 11 people, including seven US soldiers, who were killed when a Nato Black Hawk helicopter crashed in southern Afghanistan.

“Our thoughts and prayers are with those American and Afghan families who lost loved ones in that incident,” spokesman Jay Carney said.

The cause of the crash remains under investigation after the Taliban claimed responsibility, he said.

Four Afghans, including three members of the security forces and one civilian interpreter, were also killed in the crash, according to Nato's US-led International Security Assistance Force (Isaf).

A Nato Black Hawk helicopter came down in southern Afghanistan on Thursday, killing seven American soldiers and four Afghans, the military said, as Taliban insurgents claimed responsibility.

The four Afghans included three members of the security forces and a civilian interpreter, Nato's US-led International Security Assistance Force (Isaf) said.

“The cause of the crash is under investigation,” it said, adding that the helicopter was a UH-60 Black Hawk. The statement gave no further details.

Taliban spokesman Qari Yusuf Ahmadi told AFP: “Our mujahideen  shot down an Isaf helicopter in Chenarto area of Shah Wali Kot district in Kandahar province at around 11:00 am (local time).” He said a rocket-propelled grenade had been used against the helicopter.

“The helicopter was destroyed and all the crew and soldiers inside were killed,” Ahmadi said.

“The Nato helicopter was hit by a Taliban rocket in Khashir area of Chenarto village in Shah Wali Kot district this morning,” a local official who requested anonymity told AFP.

The area had been cleared of Taliban in a push by Nato and Afghan forces in 2010, but the insurgents had become active in the district again, district governor Obaidullah said.

“Taliban have been active in Chenarto village since the beginning of this year. Afghan and foreign forces have had frequent clashes with the Taliban in this district since the beginning of this year,” said Obaidullah, who uses just one name.

The Isaf statement did not use its normal phrasing for a simple helicopter crash, which includes the line that no enemy activity was reported in the area.

Helicopter crashes are fairly frequent in Afghanistan, where the 130,000-strong Nato mission relies heavily on air transport.

Last August, an American Chinook was shot down by the Taliban near Kabul, killing eight Afghans and 30 Americans, including 22 Navy Seals from the same unit that killed Osama bin Laden in neighbouring Pakistan earlier that year.

It was the deadliest single incident for American troops in 10 years of war in Afghanistan.

On March 16, a Turkish helicopter crashed into a house on the outskirts of Kabul, killing 12 Turkish soldiers and two Afghan civilians.