"A man with a long beard, wearing a black turban who identified himself as a German citizen and speaks German, was taken along with three other suspected Taliban on Monday night in Gereshk district of Helmand province," Omar Zwak, the provincial governor's spokesman, told AFP late last night.
A statement from the Afghan army corps in the province confirmed that the man had been detained with other suspects in a joint operation between Afghan Special Forces and the Afghan air force.
Gereshk police chief Ismail Khplwak said the man was the "military adviser of Mullah Nasir", commander of the Taliban's elite "Red Unit" in Helmand.
If confirmed it would be one of the few incidents in which a European has been captured fighting among the insurgents.
More From This Section
Foreigners do fight alongside the Taliban but citizens of Western nations are rare and most hail from Pakistan, Central Asia or Arab nations.
Photographs taken by the Afghan military show a man who looks to be in his 40s with a long reddish-brown beard speckled with grey, and wearing a black turban.
The man is dressed in traditional Afghan dress, a long shirt and wide trousers, worn under a khaki military jacket.
"They were in a mine-making centre when they were detained. Weapons and ammunitions were also confiscated from them," he said, adding that several Taliban were killed in the fighting.
Perhaps the most famous Western fighter with the insurgents was John Walker Lindh, the so-called "American Taliban", who was captured in Afghanistan and was sentenced to 20 years in prison in 2002.
Much of opium-rich Helmand in Afghanistan's south remains controlled or contested by the Taliban who are heavily reliant on the proceeds of drug trafficking to fuel their insurgency.
The Taliban's Red Units serve as the insurgents' special forces and have carried out many fatal attacks on the Afghan army and police.