RAMADI, Iraq (AFP) - Iraqi Prime Minister Haider al-Abadi on Tuesday visited Ramadi, a day after federal forces announced the liberation of the city from the Islamic State in Iraq and Syria (ISIS) group, clinching a landmark victory.

Abadi arrived by helicopter in the battle-scarred city, which lies around 100km west of Baghdad and is the capital of the province of Anbar, an AFP correspondent reported.

The premier vowed Monday, after counter-terrorism forces raised the flag above the key government complex in Ramadi, to rid the whole country of ISIS by the end of 2016.

It is customary for the premier to visit newly reconquered cities but he was likely to feel particularly vindicated by the victory in Ramadi, which government forces had lost in May.

Abadi was criticised at home for not resorting to the powerful Teheran-backed Shi'ite militia groups that played a key role in retaking other cities such as Tikrit and Baiji and instead coordinating with the US-led coalition.