Cameron Says U.K. Drone Killed British ISIS Fighters in Syria

Britain has for the first time conducted an air strike in Syria, killing two of its own nationals suspected of fighting for ISIS, Prime Minister David Cameron said on Monday, despite not having a parliamentary mandate to take military action in the country.

Britain conducts regular attacks in neighboring Iraq and flies drones over Syria to gather intelligence on the hardline IS group. But unlike some other coalition partners it does not target IS positions in Syria.

Cameron told parliament on Monday that, as an act of self defense, one Briton had been targeted and killed in a precision air strike carried out by an RAF remotely piloted aircraft in August. Two others traveling with the man - including another Briton - were also killed.

"There was a terrorist directing murder on our streets and no other means to stop him," Cameron said. "We took this action because there was no alternative."

Reyaad Khan, the Briton targeted in the air strike, had his assets frozen by Britain's finance ministry last year after reports that he been involved in terrorism-related activities in Syria.

"There was clear evidence of the individuals in question planning and directing armed attacks against the UK," Cameron said. "These were part of a series of actual and foiled attempts to attack the UK and our allies."

Cameron said the air strike was "entirely lawful" and the first time in modern history that Britain has used a military asset to conduct such action in a country it is not at war with.