Syrian-iraqi Border

US air strikes against Iran-backed armed groups on the Syrian-Iraqi border killed at least seven fighters overnight into Monday, sparking immediate calls for revenge and fears of a new escalation between Washington and Tehran.

Along the vast, zigzagging perimeter of the Islamic State's self-styled state, the militants are steadily being pushed back as the forces ranged against them gain in strength.

US air strikes against Iran-backed armed groups on the Syrian-Iraqi border killed at least seven fighters overnight into Monday, sparking immediate calls for revenge and fears of a new escalation between Washington and Tehran.

Along the vast, zigzagging perimeter of the Islamic State's self-styled state, the militants are steadily being pushed back as the forces ranged against them gain in strength.