The Taliban have pushed deeper into the Sangin district of the Helmand province, as the Afghan army battles to take back control of the strategically-important area. Kabul has sent reinforcements to support the troops.
The Taliban claimed Wednesday they had seized the entire district and were in control of the government buildings and police stations in Sangin.
In an online statement, the militants said the district center had been completely overrun and that they had captured large quantities of weapons and other military equipment.
The provincial government, however, said the fighting continued in the key Helmand district, as Kabul had sent more reinforcements to the area.
Battle for Sangin
The Islamists battled through the frontlines of the district on Sunday after days of clashes with the Afghan forces.
Civilians are fleeing the area after fears grew that the Taliban could capture the entire southern province.
But Mohammad Jan Rasoolyar, Helmand's deputy governor, was hopeful the government troops will regain control. "I am confident that we will not lose Sangin," Rasoolyar told AFP news agency on Wednesday.
Earlier, acting Defense Minister Masoom Stanekzai confirmed the reinforcements had arrived in Helamand. "The military is in position and the operation is ongoing," Stanekzai told media in Kabul.
Pressure is building on Afghan President Ashraf Ghani as the Afghan army faces Taliban attacks in many parts of the country.
The unrest in Helmand comes less than three months after the Islamist insurgents briefly captured Afghanistan's fifth-largest city, Kunduz.
Some commentators believe the Taliban are gaining strength. "As we have seen in Kunduz, the Afghan forces are incapable of tackling insurgency on their own," Omar Hamid, an analyst at the security consulting firm IHS, told AFP, adding that "Sangin only reinforces that image."
Helmand is a strategically-important province with major supply routes for the opium trade and its proximity to Pakistan.
British and US forces previously struggled for years to control the province, where more than 450 British servicemen and women had been killed in fighting.
shs/jm (AFP, Reuters)