BAGHDAD - Iraqi security forces on Tuesday launched a major offensive to complete the capture of the city of Ramadi, the capital of western province of Anbar, from Islamic State (IS) militants.

The anti-terrorism troops, backed by Iraqi and US-led coalition aircraft, began their advance from several directions into the central part of Ramadi, some 110 km west of Baghdad, the Joint Operations Command said in a brief statement.

On Saturday, Iraqi Defense Minister Khalid al-Obeidi said that "Iraqi forces are close to free Ramadi" and pledged that "during the next days, Iraqi forces will free the IS-held territories in the provinces of Anbar, as well as Salahudin and Nineveh."

The latest offensive came as the security forces have recently made significant advance in Ta'mim district in southern Ramadi and in several areas on the edges of the city as part of their efforts to flush out IS militants from Ramadi.

The troops have been fighting for months to retake control of key cities and towns in Iraq's largest province of Anbar from IS militants, who have seized most of Anbar and tried to advance towards Baghdad.