Two British nationals fighting for Islamic State and thought to be planning attacks against the UK have been killed by a British drone attack in Syria. 

"Today I can inform the House that in an act of self defence, and after meticulous planning, Reyaad Khan was killed in a precision air strike carried out on 21st August by an RAF remotely-piloted aircraft while he was travelling in a vehicle in the area of Raqqa in Syria. In addition to Reyaad Khan, who was the target of the strike, two ISIL associates were also killed, one of whom, Ruhul Amin, has been identified as a UK national," British Prime Minister David Cameron said.

Cameron, who didn't have a parliamentary mandate to take military action said the strike was taken because there was no alternative.

"... Both Junaid Hussain and Reyaad Khan were British nationals based in Syria who were involved in actively recruiting ISIL sympathisers and seeking to orchestrate specific and barbaric attacks against the West including directing a number of planned terrorist attacks right here in Britain..."

A third Briton fighting with IS, Junaid Hussain, was killed in a separate U.S. air strike last month.