Five Royal Marines have been charged with murder in connection with an incident in Afghanistan in 2011, the Ministry of Defence has confirmed.
Two marines were detained by Royal Military Police (RMP) over the weekend, bringing the total number of arrests to nine.
Four of those held have been released without charge.
An MoD spokesperson said those charged with murder "remain in custody pending court proceedings".
"It would be inappropriate to comment further on this ongoing investigation."
The five cases have been referred to the Service Prosecuting Authority (SPA), an independent body that conducts prosecutions on behalf of the military.
Bruce Houlder QC, the director of service prosecutions, will decide whether there is sufficient evidence to proceed to trial by court martial, which has similar powers to a crown court.
The marines were arrested on Friday after suspicious video footage was found on a serviceman's laptop by civilian police in the UK.
It is believed to be the first time UK servicemen have been arrested and charged with such charges during the Afghanistan conflict.
The charges are related to an incident in Afghanistan last year, when Royal Marine 3 Commando Brigade was based in Helmand.
The MoD previously said the incident followed an "engagement with an insurgent" and no civilians were involved.
During a six-month tour of duty, which lasted from April to October last year, seven servicemen from 3 Commando Brigade were killed in action, all from 42 Commando.