The Islamist group says Britain has made a “stupid decision” by sending troops back to Helmand province as its fighters battle Afghan forces for control of the strategic town of Sangin.
A team of around 10 British soldiers has been deployed to Camp Shorabak in Helmand as part of a wider Nato mission to help local forces. The Ministry of Defence (MoD) says the UK team is working in an advisory role only.
The move came after insurgents overran Sangin, taking control of most of the district and surrounding Afghan government forces.
Acting defence minister Masoom Stanekzai said fighting was ongoing in Sangin, but reinforcements had arrived to relieve troops.
“The military is in position and the operation is ongoing,” he told a press conference in Kabul.
Provincial police chief Abdul Rahman Sarjang said the situation had improved since the beginning of the week but heavy fighting was continuing.
Helmand district governor Mohammad Jan Rasoulyar told the BBC the Afghan National Army (ANA) was “now taking the fight to the Taliban”.
There are reports of fighting across Helmand, a traditional Taliban stronghold and opium-growing district, which British and US forces fought for years to control.
Some 106 British service personnel lost their lives in Sangin district between 2006 and 2010.
Afghan forces have struggled to contain the insurgency since overseas troops stood down combat operations last year. Government soldiers have complained about being left without adequate supplies, reinforcements or air cover.
Taliban militants seized the city of Kunduz for several days in September in a show of strength that came amid reports that its forces were being squeezed by the rival Islamic State group.
And on Wednesday, the Taliban claimed to have captured the district of Gulistan in Farah, a remote western province, but governer Asif Nang said the claim was “baseless”.
The Taliban has issued a statement on Britain’s renewed involvement in Helmand, saying: “Our message to the British government and people is before attacking Afghanistan is to read the history of your forefather’s (sic), and you should have learnt from their repeated defeat in Afghanistan.
“They suffered great losses and left this place now once again they came here that’s a stupid decision.
“The Afghan people are ready for any kind of sacrifices to defend their country and we will continue our fighting.
“The involvement of the British forces once again showed to the world that with all those modern equipment the Kabul administrator isn’t capable in controlling or holding the ground.
“It’s proved that without foreign support the Kabul administration cannot protect their selves and it will be hard for them to function.”
Former foreign secretary David Miliband, who now heads the International Rescue Committee in New York, said the situation was “on the verge of becoming desperate”.
He told BBC Radio 4’s Today programme: “We are paying the price of missed opportunities in the second term of president Karzai from November 2009 for five years.
“I think that for Britain now – given the level of sacrifice but also the importance strategically of Afghanistan of an entry point into central Asia, as a potential expansion ground for Isis and others – I think it is important for Britain to be part of the overall strategy to stabilise the country. Above all that needs to be a political strategy.”