The marines had been on patrol with Afghan forces
Two Royal Marines have been killed in an explosion which hit their vehicle on patrol in southern Afghanistan.
The pair, from UK Landing Force Command Support Group, died in the blast in the Garmsir district of Helmand province on 12 November.
The families of both marines, who served with the Plymouth-based 3 Commando Brigade, have been notified.
The total of UK military deaths in Iraq and Afghanistan has now reached 300 - 124 of them in Afghanistan.
Cdr Paula Rowe, of Task Force Helmand, said: "Our thoughts and prayers are with them at this terrible time."
She added: "This is a tragic blow to us all in the task force, but our loss is nothing compared to that of their families and loved ones."
'Peace and stability'
The MoD said the marines had been taking part in a joint patrol with Afghan soldiers when the explosion happened at 1647 local time (1217 GMT).
They had been working with Task Force Helmand's Information Exploitation Group.
Brig Gen Richard Blanchette of the Nato-led International Security Assistance Force (Isaf) said: "Our deepest sympathies go out to their family, friends and fellow soldiers.
"Their lives are irreplaceable to all of us who fight for the peace and stability of Afghanistan."
Meanwhile, Afghan President Hamid Karzai, speaking after talks with Prime Minister Gordon Brown in Downing Street, has said all efforts are being made "to bring violence down" in Afghanistan.
His comments came after a bloody 24 hours in which one US soldier and at least 18 civilians, as well as the two British marines, were killed.
President Karzai insisted violence in Afghanistan was not increasing, saying it was at the same level "as it was for the past year or two".