The helicopter came down late Friday in the eastern province of Wardak, southwest of the capital Kabul, said provincial spokesman Shahidullah Shahid.

A spokesman for the NATO-led International Security Assistance Force (ISAF) said it was still looking into what had happened.

But an eyewitness told AFP that the helicopter had crashed as it was trying to take off after landing on the roof of a Taliban commander's home during a fire-fight.

Shahid said, "The joint forces (foreign and Afghan) conducted an operation against the Taliban in Sayd Abad district last night.

"Eight insurgents were killed. A coalition helicopter that was firing on insurgents at the time crashed.

"We're not sure if this happened due to insurgent fire or not but there were some casualties of foreign troops due to the crash."

One man who said he saw what happened, Mohammad Saber, told AFP that the helicopter had come down after an operation in his village.

"At around 10:00pm last night (1730 GMT), we heard helicopters flying over our village," he said.

"We were at home. We saw one of the helicopters land on the roof of a house of a Taliban commander, then shooting started.

"The helicopter later took off but soon after taking off it went down and crashed. There were other helicopters flying as well."

A spokesman for ISAF, the foreign military force in Afghanistan, said they were currently assessing what had happened.

"An International Security Assistance Force helicopter crashed in eastern Afghanistan today and recovery operations are under way," he said.

"ISAF is still in the process of assessing the circumstances to determine the facts of the incident. Reporting indicates there was enemy activity in the area."

Taliban spokesman Zabiullah Mujahid said the insurgent group was responsible for shooting down the helicopter and acknowledged that eight of its fighters had been killed.

The militia frequently exaggerates claims in relation to attacks in Afghanistan.

There are currently around 140,000 foreign troops in Afghanistan, around 100,000 of them from the United States, fighting as part of the international force that has been in the country for almost ten years.

Some troop withdrawals have already begun as part of a process which is due to see all foreign combat forces leave the country by the end of 2014.

However, the Taliban are still waging a bloody insurgency in the country. In recent weeks, a string of high-profile figures close to President Hamid Karzai have been assassinated.

And in June, the United Nations said that the number of security incidents between March and June was up over 50 percent on the same period last year.

Copyright AFP (Agence France-Presse), 2011