A Royal Marine and a woman soldier have died from injuries received while on patrol in Afghanistan.
The Royal Marine, from 40 Commando and the soldier, from 3 Medical Regiment, were on patrol in the Nahr-e Saraj district of Helmand province when they were killed on Wednesday, the Ministry of Defence (MoD) said. Their families have been informed.
The soldier is a 25-year-old woman from Comber in Co Down, Northern Ireland, the Belfast Telegraph said, though the MoD was unable to confirm this.
The pair are thought to have been killed by insurgents, though the BBC said an Afghan source claimed the deaths were from a "green on blue" attack - where coalition troops are killed by their Afghan allies.
A source said it understood the Taliban had issued a statement in Afghanistan suggesting the incident was a green on blue attack.
But the source said the details of the incident were still unclear because the people who knew what happened were not in a "state" to write down witness statements or explain what they saw.
The source said the Marine and soldier appeared to have been killed by gunshot wounds by insurgents, but the details had not yet been confirmed.
Major Laurence Roche, spokesman for Task Force Helmand, said: "I am extremely sorry to announce the deaths of a Royal Marine from 40 Commando and a soldier from 3 Medical Regiment serving with Task Force Helmand.
"This is dreadful news for all of us serving in Afghanistan. Our sincere condolences go to their families, friends and colleagues at this time of grief."
Their deaths take the total number of UK service members to have died since operations in Afghanistan began in October 2001 to 435.