French President Francois Hollande congratulated Iraqi Prime Minister Haider al-Abadi on his army's liberation of Ramadi from Islamic State forces on Monday, saying it was "a major step" in the conflict.

"(Hollande) congratulated him on the liberation of the town of Ramadi by Iraqi forces, which constitutes the most important victory since the start of the fight against the terrorist organisation Daesh (an alternative name for ISIS)," the president's office said in a statement following a phone call between the two leaders.