A British soldier killed in an explosion in southern Afghanistan was from 29 Commando Regiment, Royal Artillery, the MoD has said.
His name is expected to be released on Friday, after his next-of-kin requested an extra 24 hours before it was made public, said officials.
Three others were injured in the blast, during a reconnaissance mission in desert south of Garmsir, Helmand.
The cause is not known, but there are suggestions it could have been a mine.
One of the wounded servicemen was seriously hurt and the other two sustained minor injuries.
The man seriously injured had been operated on and was "doing well", said Lieutenant Colonel Andy Price, of the Royal Marines.
The Plymouth-based regiment is the Close Support Artillery Regiment that supports 3 Commando Brigade Royal Marines.
Lt Col Price said: "A patrol had gone out on a reconnaissance to look at a specific piece of land and there was an explosion.
"It could have been a legacy mine from many years ago or it could have been a deliberate attack on us, though it's unlikely as it was in the middle of the desert," he told Sky News.
The MoD said there were no Taleban forces in the area at the time.
The Commander of the UK Task Force, Brigadier Jerry Thomas, said his thoughts and condolences were with the dead serviceman's family, friends and colleagues.
He said the sense of tragedy was heightened by the fact that it had taken place "during this special time of the year".
"My thoughts are also with the soldier who was seriously injured and I wish him a speedy recovery," he said.
Brig Thomas added: "The soldier's colleagues remain on the ground and are continuing with their task, despite their loss.
"They are determined to complete their mission."
The number of UK troops killed while on operations in Afghanistan since 2001 is now 44.
Of the 44, 21 died from accidents, illness, or non-combat injuries, according to the MoD.