A British soldier has been shot dead while manning a checkpoint in southern Afghanistan, the Ministry of Defence (MoD) has said.
Troops are taking part in an offensive against the Taleban
The soldier, from the 1st Battalion The Grenadier Guards, came under attack near Garmsir in Helmand Province early on Thursday.
Relatives have been informed and have requested a period of grace before more details are released.
Fifty-four British troops have been killed in the country since 2001.
In a statement, the MoD expressed "deep regret" at the death.
The soldier was part of a team manning one of three checkpoints in the area.
At 0645 local time (0315 BST) the checkpoint was attacked by eight to 10 lightly-armed Taleban fighters, said the MoD.
In a subsequent gun battle the soldier was shot. He was flown to Camp Bastion, the main British base in the area, but medical personnel were unable to save his life.
The firefight continued for nearly two hours, with two Dutch jets called in to provide air cover.
Eventually a 500lb (227kg) bomb was dropped on the Taleban firing position, and the remaining members of the dead soldier's team were relieved by incoming troops and allowed to return to base.
Nato's regional commander Major General Jacko Page said: "Our thoughts are with the family, friends and colleagues of the soldier who died.
"This tragic loss will be felt right across the multi-national task force."
British forces are taking part in a major military offensive against the Taleban in southern Afghanistan.
Up to 3,000 Nato troops, including Afghans and US forces, are involved in the British-led Operation Silicon in the Sangin Valley, Helmand province.