Image caption Reyaad Khan, from Cardiff (L) and Ruhul Amin, from Aberdeen, travelled to Syria to fight with the Islamic State group

Two British Islamic State jihadists killed by an RAF drone strike in Syria were cousins, the BBC has learned.

Cardiff-born Reyaad Khan, 21, and Ruhul Amin, 26, from Aberdeen, died in August in Raqqa, alongside another fighter.

Relatives of Khan in Bangladesh confirmed the relationship between the two militants, and said Khan, who was thought to be planning an attack on the UK, had been brainwashed in Britain.

They told the BBC the family was shocked by his decision to join IS.

They also said prayers had been said for the men at mosques in their village in north-east Bangladesh.

'Barbaric'

Khan was killed in a precision strike on 21 August by a remotely-piloted aircraft, while he was travelling in a vehicle.

Initial reports said Khan was killed by a US drone strike, but earlier this month, Prime Minister David Cameron announced it had been a British operation.

The strike on Khan was "the first time in modern times that a British asset has been used to conduct a strike in a country where we're not involved in a war", the PM told the House of Commons.

Khan had been plotting "barbaric" attacks on "high-profile public commemorations" in the UK, he said, and the attack was a lawful "act of self defence".

Two years ago MPs rejected possible UK military action in Syria, but last September approved British participation in air strikes against IS targets in Iraq only.

Senior politicians and human rights groups raised concerns about the legality of the unprecedented drone strike, and called for the House of Commons Intelligence and Security Committee to investigate.

Family friends of Khan, along with Muslim leaders in Cardiff, have asked for proof of his involvement in plots to attack the UK.