Ramadi liberation 'most important victory yet' against IS: French president

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," the president's office said in a statement following a phone call between the two leaders.

"It's a major step in the re-establishment of the authority of the state in Iraq," the statement added.

Iraqi forces raised the national flag over the government complex in central Ramadi earlier on Monday.

The IS group had an estimated force of around 400 fighters to defend central Ramadi a week ago. It is not clear how many were killed and how many were able to pull back to positions outside the city.