A female British Army medic killed in Afghanistan has been named locally as Channing Day, 25, from Northern Ireland.
Miss Day, who served with 3 Medical Regiment, died alongside a Royal Marine from 40 Commando and a suspected Afghan insurgent while on patrol in the Nahr-e Saraj district of Helmand Province.
The soldier from Comber, Co Down, was a bubbly and sporty teenager who dreamed of joining the Army as a schoolgirl, a former teacher said.
Strangford College acting principal Paul Maxwell said: "She always said she wanted to join the Army, she was pretty much focused on wanting to join the Army."
The families of the British personnel have been informed of their death.
The Taliban claimed the incident as a "green on blue" attack, but the MoD said the Afghan man - although believed to be a member of the Afghan Uniformed Police - was not wearing uniform at the time and was not on patrol with British troops.
An MoD spokesman said: "On October 24, during a UK foot patrol in the Nahr-e Saraj district of Helmand Province, there was an exchange of gunfire that resulted in the deaths of a Royal Marine from 40 Commando Royal Marines, a female soldier from 3 Medical Regiment and an Afghan man who is believed to be a member of the Afghan Uniformed Police but who was not wearing uniform at the time. The UK patrol were not working with any Afghan partners at the time."
The spokesman said an investigation is continuing into what initiated the exchange of gunfire but the situation "remains unclear".
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.