KANDAHAR, Afghanistan (Reuters) -- A helicopter has crashed with casualties in Afghanistan's southern Helmand Province, scene of a massive operation by U.S. Marines, officials said.
An Afghan official who witnessed the crash told Reuters the helicopter was being used by foreign forces, but spokesmen for the British and U.S. said it was a civilian aircraft.
"We are aware of an incident involving a non-British military helicopter in Helmand Province," Lieutenant-Colonel Nick Richardson of the NATO-led force told Reuters by phone from the province.
A spokeswoman for the U.S. Navy, Lieutenant Commander Christine Sidenstricker, said there had been some casualties.
"At this time, I can tell you that a civilian helicopter crashed in Sangin. We know that there were casualties, but we are still receiving information from the scene and at this time do not have any additional details about them," she told Reuters.
Sangin's district chief Fazlul Haq said he saw a chopper on fire before it crashed. "It was in the sky on fire and then went down," he told a Reuters reporter in the south.
The Taliban, leading the insurgency against foreign troops and the Afghan government, said the militant group had shot down a Chinook helicopter in Helmand.
The crash comes amid an offensive by some 4,000 U.S. Marines and hundreds of NATO and Afghan forces in various parts of Helmand against the Taliban, the biggest by foreign troops since they ousted the Islamist group in 2001.
More than 15 foreign servicemen have been killed since the start of the assault in Helmand, part of the main bastion for Taliban guerrillas and the main drug producing region of Afghanistan, the world's top supplier of heroin.
Several dozen Taliban have also been killed, according to Afghan government, but there has been no major engagement with the militants.
Last week, three foreign servicemen were killed when a NATO helicopter crashed in southern Zabul Province.
Since the launch of the operation in Helmand, the Taliban have also stepped up their attacks in other parts of Afghanistan against foreign troops and the Afghan government, making July as the bloodiest month for foreign troops for nearly a year.