LASHKAR GAH, Afghanistan (Reuters) - U.S. aircraft carried out two attacks in Sangin, the district in southern Afghanistan overrun by Taliban insurgents this week, officials said on Thursday.
The fierce fighting in Helmand, a traditional Taliban stronghold and one of the world's main centers of opium production, has piled pressure on President Ashraf Ghani, already on the defensive as security worsens across the country.
The Taliban, who already control almost all of Sangin district, said on Wednesday that they had captured police and administrative buildings in the district center, where small groups of police had been holding out.
However government officials have denied the claim and said they have pushed back Taliban insurgents seeking to re-establish their hard-line Islamist regime after being toppled by U.S.-led military intervention in 2001.
General Abdul Wodud, a senior army commander, said a joint Afghan and NATO operation backed by air support had driven the Taliban back from central areas, killing 60 Taliban fighters and wounding 40.
The interior ministry also said that security forces had killed a senior Taliban commander it identified as Mullah Nasir.
NATO headquarters in Kabul confirmed that the air strikes had taken place but gave no details.
"U.S. forces conducted two strikes in Sangin district, Helmand Province, December 23, against threats to the force," U.S. Army Colonel Michael Lawhorn said.
The Taliban already held three Helmand districts as well as large parts of the rest of the province outside the main centers and control strategic roads, making it hard to reinforce and resupply security force units cut off by their advance.
But the loss of Sangin, which British and U.S. forces fought for years to control, would also be a heavy blow for Western powers backing the Kabul government, now fighting alone since international forces ended combat operations last year.
Despite billions of dollars in aid and thousands of deaths among international forces, the capacity of Afghan security forces to stand alone has been called into question by the Helmand fighting as well as by earlier episodes such as the fall of Kunduz, which the Taliban captured briefly in September.
Widespread reports of mass desertions, leadership confusion and bitter complaints from the frontline about units being left for months without reinforcements or adequate supplies have underlined the problems facing Afghan commanders.
NATO military advisers have been sent to Helmand, with an extra British contingent arriving this week, but officials say they have a purely advisory role and they have not confirmed reports that special forces units are present.
The Taliban issued a statement saying that foreign forces were directly involved in the fighting in Sangin and accusing them of carrying out airstrikes on residential areas.
Reporting by Mohammad Stanekzai; Writing by James Mackenzie; Editing by Nick Macfie/Ruth Pitchford