A US soldier has become the first American killed in Afghanistan in 2016 while two more were wounded in an operation in Helmand province, where Afghan troops are battling Taliban insurgents.

A US soldier has become the first American killed in Afghanistan in 2016 while two more were wounded in an operation in Helmand province, where Afghan troops are battling Taliban insurgents, US and NATO officials said.

The troops had come under fire while conducting a mission Tuesday with Afghan special operations counterparts in Marjah, Pentagon press secretary Peter Cook said.

An unspecified number of Afghan troops were also wounded in the mission, officials said.

Afghan forces are currently fighting to repel Taliban militants who in recent weeks have seized large swathes of the key opium-rich district of Sangin in the southern province of Helmand, a traditional stronghold of the insurgents.

In December, the Taliban offensive prompted the first British deployment to the volatile province in 14 months.

The deployment, in addition to a recent arrival of US special forces in the region, comes a year after NATO forces formally ended their combat operations in the country.