Two Royal Marines have been killed in an explosion in the Nad Ali district of Helmand province in Afghanistan, Britain's Ministry of Defence (MoD) announced Saturday. The British soldiers were said to have been on patrol 'disrupting insurgent activity' when they were hit by a blast from an improvised explosive device on Friday. The deaths come after another UK soldier was killed in an explosion in Nahr-e Saraj district of Helmand on Monday and bring the number of British military deaths in Afghanistan to 368 since the overthrow of the Taliban regime in 2001. On Thursday, Britain's former ambassador to Afghanistan Sir Sherard Cowper-Coles stepped up his criticism of the 10 year old war, attacking the conduct of the US commander, General David Petraeus and describing the future CIA chief's tactics as counter-productive and 'profoundly wrong'. 'He has increased the violence, trebled the number of special forces raids by British, American, Dutch and Australian special forces going out killing Taliban commanders, and there has been a lot more rather regrettable boasting from the military about the body count,' Cowper-Coles warned.