An Afghan policeman suspected of shooting dead three British soldiers has been named as Ziarahman, by the head of Afghanistan's police.
The two soldiers from the 1st Battalion Welsh Guards and another from the Royal Corps of Signals were killed on Sunday. They are expected to be named later.
They were shot as they left a checkpoint in Helmand province.
Ziarahman, who reportedly came from Herat in western Afghanistan, was injured and later detained.
More than 20 foreign personnel have been killed in rogue shootings in Afghanistan this year.
Such shootings are sometimes referred to as "green on blue" attacks because of the colours representing Afghan (green) and Nato (blue) forces.
The soldiers were part of a Nato-led Isaf force who have been training Afghan counterparts ahead of a handover of security responsibility by 2014.
The shooting happened at Checkpoint Kamparack Pul in Nahr-e-Saraj, southern Afghanistan, where the soldiers were attending a meeting of elders.
'Appalling news'They received first aid but died of their injuries at the scene.
Sources told the BBC a fourth British soldier was injured in the shooting but was not seriously hurt.
Defence correspondent Caroline Wyatt, in Lashkar Gah, the capital of Helmand province, says the Afghan policeman remains in custody.
Ziarahman had been a member the Afghan National Civil Order Police for nine months, said the head of the police force, Ghulam Zaki Ghafory. He had been in Helmand for just over two months.
Prime Minister David Cameron said on Monday that he was "deeply saddened by the appalling news".
