Reports from the southern Afghan province of Helmand suggest Taliban militants are close to overrunning the strategically important town of Sangin, BBC News reports.

Helmand's governor, Mirza Khan Rahimi, insisted the authorities were still in control but his own deputy said that Sangin had been overrun.

The Taliban said they controlled most of the town and the main administrative building had been abandoned.

In the east, a Taliban attack near Bagram killed six US soldiers.

Some 12,000 foreign soldiers are deployed as part of the Nato-led Resolute Support international coalition, which is meant to underpin Afghanistan's own security forces.

The battle for Sangin comes a little over a year after the end of UK combat operations in Afghanistan, in which at least 450 soldiers were killed.

During its deployment in Helmand, the British military suffered its heaviest losses in Sangin.

Governor Rahimi gave a news conference in Helmand's provincial capital, Lashkar Gah, after his deputy, Mohammad Jan Rasulyar, told international news agencies Sangin had been overrun by the Taliban late on Sunday.

"The Taliban have captured the police headquarters, the governor's office as well as the intelligence agency building in Sangin," Mr Rasulyar told AFP. "Fighting is escalating in the district."

Quoted by the Associated Press, he said casualties among Afghan security forces were high but he gave no figures. Only some army facilities had not been taken, he added, according to BBC.