Iraqi forces 'take back towns from IS'

An Iraqi security official says government forces have made progress in an anti-Islamic State offensive south of Ramadi.

Iraqi forces have recaptured towns from IS fighters near militant-held Ramadi, officials say. (AAP)

Iraqi forces have recaptured towns from Islamic State fighters near militant-held Ramadi, a security official says.

The official, a member of the Anbar police command, said security forces backed by Shi'ite militias and local tribes had regained control of Tash and Hamira south of Ramadi, cutting off IS supply lines in the area.

Meanwhile, a pro-government Shi'ite militia, known as the Popular Mobilisation, said it had advanced into the area of Nabai near Ramadi, forcing the extremists to retreat.

"Daesh elements escaped once the ... Mobilisation fighters entered into Nabai," Hassan al-Sari, a field commander in the militia, told Iraq's Alsumaria news, using an Arabic acronym for IS.

He added that the major militia force had pushed around 20 kilometres deeper into the area.

The claims could not be independently verified.