WASHINGTON (AFP) - The US military unleashed a wave of air strikes against Islamic State (ISIS) extremists in Syria and Iraq this weekend, destroying tanks, armoured vehicles and mortar teams, a statement said Sunday.

US fighter aircraft carried out three air strikes in Syria on Saturday, while fighter jets, bombers and helicopters were used in six assaults against ISIS positions in Iraq on Sunday, US Central Command said in a statement.

An airstrike in Syria northwest of Al Mayadin destroyed a bulldozer, two tanks and another vehicle.

Twin strikes northwest of the ISIS group's Raqa stronghold pounded an ISIS unit and destroyed six firing positions, the statement said.

In Iraq, four strikes northeast of Fallujah hit two mortar teams, a large ISIS unit and two smaller units. Three Humvees were destroyed in two more attacks near Hit and Sinjar, the statement said.

The strikes come after a global wave of revulsion triggered by the IS group's beheading of British aid worker Alan Henning, made public in a video that emerged on Friday.

The US launched air strikes in Iraq in August before widening the campaign to include targets in Syria last month.