One US service member was killed and two wounded in an operation near Marjah in Afghanistan's Helmand province, a NATO defence official said Tuesday.

"We are deeply saddened by this loss," said Brigadier General Wilson A. Shoffner, the spokesman for the NATO mission in Afghanistan, adding "our heartfelt sympathies go out to the families and friends of those involved".

A US defence official told AFP on condition of anonymity that it was a special operations mission and Afghan soldiers were also wounded.