Two RAF personnel from the 230 and 33 Squadrons died when their Puma Mk 2 aircraft crashed while landing at NATO base Resolute Support in the capital Kabul.

Five others were injured.

A spokeswoman for the Ministry of Defence said: "The incident is currently under investigation but we can confirm that it was an accident and not the result of insurgent activity."

Their relatives have been informed and have requested a period of grace before their names are released, she said.

All five killed were from Resolute Support, a NATO-led mission to train Afghan security forces following the stand-down of the International Security Assistance Force last year.

Around 500 British troops remain in Afghanistan as part of the mission.

The latest deaths bring the total number of British forces personnel or MoD civilians killed while serving in Afghanistan since the start of operations in October 2001 to 456.

Earlier on Sunday, at least three people were injured in a suicide attack on a convoy of British troops in Kabul.

Three civilians suffered minor injuries after the bomber drove his car into the armoured vehicle during rush-hour, causing slight damage to it.