A Royal Marine was killed today during a mission to oust Taliban insurgents in southern Afghanistan, the Ministry of Defence said.
The serviceman, from 45 Commando Royal Marines, died during an operation targeting known Taliban positions and firing points near Garmsir in Helmand province, the MoD said.
Nato officials said soldiers were attacking a militant base when they were "engaged from several insurgent positions".
He is the second British serviceman to die in the country in the past three days, after 21-year-old Royal Marine Thomas Curry, from east London, was killed during a battle to clear Taliban positions on Saturday.
Commander of the UK Task Force in Afghanistan Brigadier Jerry Thomas said the latest death occurred during a "substantial" and "important" operation, and that his thoughts were with the serviceman's family.
"Sadly, one of our marines was killed during an important operation in southern Helmand.
"I do know that this is a very difficult time for his family and his friends, but I do want to convey my sincere condolences and let them know that our thoughts are very much with them," he said.
"Our marine was killed during a substantial pre-planned operation in the south of Helmand.
"His colleagues were able to display their courage and resolve in continuing their mission at a particularly challenging time."
The marine's next of kin have been informed of his death, the MoD said.
The latest fatality follows the deaths of two British servicemen in Afghanistan and Iraq on Saturday, in the bloodiest day for the military overseas since November.
Marine Curry, of 42 Commando, was "courageously" leading from the front to oust insurgents when he came under enemy fire in Afghanistan, the MoD said.
Meanwhile, Kingsman Alex Green, 21, from Warrington, was killed during a patrol in Basra, Iraq.
The soldier, of the 2nd Battalion The Duke of Lancaster's Regiment, died after being hit by gunfire in the Hayy Al Muhandisn district of Basra City.
Marine Curry died when elements of 42 Commando took part in a "deliberate offensive" against the Taliban near Kajaki, in northern Helmand province.
Commandos were engaged in close-quarter fighting with the enemy when Marine Curry was hit by gunfire and killed instantly.
His commanding officer, Lieutenant Colonel Matt Holmes, said: "The tragic loss of Marine Curry is felt deeply by all, a reflection of what he brought to life and all those who knew him.
"Tom died displaying the qualities so typical of him, that had rapidly earned him the respect of his colleagues.
"He was at the front, courageously closing with the enemy, with no thought for his own safety, just that of his colleagues who were close by.
"He was a glowing example of what a Royal Marine represents: courageous, robust and highly professional."
Commander of the UK Task Force in Afghanistan, Brigadier Jerry Thomas, said: "I send my sincere and heartfelt condolences to his family and to his friends.
"They have lost a much loved member of their family and a good friend and my thoughts are with them at this difficult time."
Kingsman Green, a father who leaves behind a two-year-old son called Bradley, was serving with Chindit Company, based at the Old State Building in the centre of Basra.
He was part of a patrol escorting a convoy out of the city and they were returning from their task when he was shot, the MoD said.
The MoD said he had been spotted by colleagues and commanders as a "professional soldier" with "leadership and command potential".
A spokesman said: "He was an immensely proud and devoted father who liked nothing more than to spend time with his son, Bradley.
"In particular, he enjoyed taking him to the park in Warrington and playing Pink Floyd songs to him on a guitar."
His family said in a statement: "Alex loved the Army and the services. It was all he had wanted to do.
"He had been a Marine Cadet and wanted to join the Marines but an injury prevented that, so he joined the Army.
"He was living his dream. He was proud of being in the Army and doing his duty."Reuse content