Military planes have air-dropped food and ammunition to besieged Afghan forces battling to flush out Taliban insurgents from Sangin, officials said Tuesday, two days after the emboldened militants stormed the strategic opium-growing district. Islamists in Helmand have captured large swathes of the district that British and US forces struggled for years to defend, tightening their grip on the volatile southern province. Fleeing local residents reported bloody gunfights as the Taliban advanced on the district center, highlighting a worsening security situation across Afghanistan a year after NATO formally ended its combat operations. "We are air-dropping food supplies, military equipment and ammunition to support our forces in Sangin," defense ministry spokesman Mohammad Radmanesh said. "Sporadic fighting is going on around the district," he said, rejecting reports of high military casualties and asserting that the district had not fallen. A resident who fled Sangin said that insurgents had publicly executed at least three security officials after storming key government buildings. "The Taliban dragged two intelligence officials and a local police commander from their homes and shot them dead," Haji Abdul Qader said. "Only the governor's compound and the police headquarters are under government control. The rest have been overrun by the Taliban." Qader said he fled to the provincial capital Lashkar Gah after a mortar landed on his house, wounding his infant son and daughter. His testimony bore chilling similarities of the situation in Kunduz after the Taliban briefly captured the northern city in September — their most spectacular victory in 14 years of war. Taliban death squads were accused of summary executions, rape and plundering Kunduz city as NATO-backed Afghan forces struggled for two weeks to evict them. Highlighting the gravity of the situation in Sangin, seen as a hornet's nest of insurgent activity, US and British forces were recently deployed in Helmand to advise and assist Afghan forces. This month marks a year since the NATO mission in Afghanistan transitioned into an Afghan-led operation, with allied nations assisting in training local forces. US President Barack Obama in October announced that thousands of American troops would remain in Afghanistan past 2016, backpedalling on previous plans to reduce the force and acknowledging that Afghan forces are not ready to stand alone. Sangin, a strategically important district at the centre of Afghanistan's lucrative opium trade, has been the scene of fierce fighting for years between the Taliban and NATO forces. British troops fought deadly battles in Sangin for four years to little effect, before US marines replaced them in late 2010 and finally pulled out themselves last year.