Iraqi troops, backed by Shiite and Sunni tribal militiamen, launched on Tuesday a broad military campaign to liberate the western province of al-Anbar from the control of the Islamic State.
State television Al-Iraqiya announced the start of the offensive without providing further details.
Large areas of al-Anbar are under IS control, while the group seized the provincial capital, Ramadi, on May 17.
A security official told Efe that Iraqi forces advanced on Ramadi earlier on Tuesday, and reached al-Anbar University, in the south of the city.
The campaign is supported by the U.S.-led international coalition and troops from the army and the police, Shiite militiamen, and Sunni tribal fighters, according to the official.
Iraqi Prime Minister Haidar al-Abadi had told BBC television on Monday that Ramadi could be recovered "in days," but stressed that the support of the international community would be required.