Five Royal Marines have been charged with murder in relation to an incident in Afghanistan last year, the Ministry of Defence said today.
Royal Military Police had arrested a total of nine marines on suspicion of murder and four have now been released without charge pending further inquiries.
The ministry said the remaining five marines' cases had been referred to the independent Service Prosecuting Authority (SPA).
"Following direction from the SPA these marines have now been charged with murder and they remain in custody pending court proceedings."
The soldiers are believed to be members of 3 Commando Brigade and the incident was said to have occurred while they were based in Helmand.
The ministry described it as "an engagement with an insurgent" in which no civilians were involved.
During a six-month tour of duty to October seven servicemen from 3 Commando Brigade were killed in action, all from 42 Commando.
Defence Secretary Philip Hammond said he could not comment on the present case but he was determined that rules of engagement should be followed.
He told the BBC1's Andrew Marr Show: "Everybody serving in theatre knows the rules of engagement, they carry cards in their uniforms with the rules on them in case they should need to remind themselves."
Rules of engagement, never made public, are largely derived from the Geneva Convention and dictate under what circumstances British troops are allowed to open fire.
The arrests are thought to be the first time British servicemen have been held on suspicion of such charges during the conflict in Afghanistan.