Taliban forces are on the verge of overrunning the key district of Sangin district in the north of the country's notorious Helmand Province, it has been reported. Yet government officials have repeatedly asserted that the opium-rich region is safe.

An Afghan commander has told the BBC that most of the district had already been taken and the government now controls just a few square miles of the provincial capital Sangin City, and even those areas are now under threat. Eight Afghan soldiers were killed and nine were taken alive when the Taliban overran a base called "Sahra Yak" three days ago, the commander, who did not wish to be named, told the broadcaster, adding that all the weapons and ammunition were seized, including an armoured vehicle.

"Two other camps are also under threat, if they don't get the support needed, God forbid, they will have the same fate," he said.

It was unclear whether there were any British or Nato forces are in the region. A spokeswoman told told the IBTimes UK that the latest figures showed that there were 470 British troops in the country.

She did not elaborate on what role they were playing, but after reports in December that the SAS and US Special Forces troops had joined the Afghan Army to battle the Taliban in the region, a Ministry of Defence (MoD) spokesman told the IBTimes UK that a small number of UK military personnel had been deployed to the region "in an advisory role".

He said they were "mentoring and supporting the Afghan forces there".

"There are only a small number in Helmand itself as part of Nato's resolute support mission, he said, adding that the MoD did not "talk or give any guidance on special forces."

A US soldier was killed and two wounded in a January operation in Afghanistan's Helmand province, where Afghan troops are battling to push back Taliban insurgents, US and NATO officials said.

The troops had come under fire while conducting a mission with Afghan special operations counterparts in Marjah, Pentagon press secretary Peter Cook said.

Opium country

December marked the first anniversary of Nato handing over security operations to the Afghans. Before that, British and US forces struggled for years to hold on to Sangin, a fertile area that is a juncture to one of the biggest poppy growing regions in the world.

UK troops handed control over to the Americans in 2010. More than 100 of the 450 British troops killed during the campaign in Afghanistan died in Sangin.

Sangin "was significant because of the routes it controlled and it was a very significant part of the resourcing of the political economy of Helmand, because it is a major center of drugs processing and drugs shipping," Stuart Gordon, a Helmand expert at the Chatham House thinktank told the Press Association in December.

If the Taliban took control of Sangin, they would control supply routes to the districts and gain valuable influence over neighbouring provinces, he added.

December's fighting in the region was so fierce that the deputy governor of Helmand province, Mohammad Jan Rasolyaar, took the unusual step of posting an open letter to Afghanistan's President Ashraf Ghani on Facebook.

"Your Excellency, Facebook is not the right forum for speaking with you, but as my voice hasn't been heard by you I don't know what else to do," he wrote. "Please save Helmand from tragedy. Ignore those liars who are telling you that Helmand is secure."