It's understood two British jihadists killed by an RAF drone strike in Syria were targeted for recruiting Islamic State supporters online.
Britain's Defence Secretary says similar operations may be carried out in future for national security reasons.
But opposition MP's are demanding more details on the initial raid.
British Prime Minister, David Cameron confirmed yesterday the two men were killed on August 18th as an “act of self-defence”.
Reyaad Khan, from Cardiff, and Ruhul Amin, from Aberdeen, were killed in the strike, which was ordered without Commons approval.
A third Briton, Junaid Hussain, was killed in a US airstrike, six days later, on August 24, the Prime Minister said.
Major General Jonathan Shaw - who led British forces in Basra in Iraq - says if they were a threat, it was the right thing to do.
He said: “The primary consideration is were these people validly recognised member of ISIS and therefore an enemy of the international ordered community and therefore they got what was coming for them.”
Reports say a human rights group is launching legal action to force the British government to reveal the advice it received from lawyers which justified the killing of British jihadists inSyria.
The move by Rights Watch (UK) comes as critics branded the threat by Michael Fallon, the defence secretary, to target other militants overseas as operating a US-style “kill list”.
