Iraqi forces on Tuesday retook the last area of Mosul that was still under the control of the Islamic State group east of the Tigris River, the military said in a statement.

"Units from the 9th armoured division... completely liberated Al-Rashidiyah," a statement from the Joint Operations Command coordinating the fight against IS said.

"The Iraqi flag was raised and the left side (east bank) was thus fully liberated," said the statement, that also mentioned two other rural areas on the northern edge of Mosul.

Commanders from the elite Counter-Terrorism Service that has done most of the fighting and Prime Minister Haider al-Abadi had already declared east Mosul "liberated" last week.

All central Mosul neighbourhoods on the east bank of the Tigris River that divides the city had already been retaken from the Islamist militants in recent days, marking the end of an important phase in the fighting.

Top commanders and their foreign partners are now devising a strategy to tackle the IS-controlled west bank of Mosul, which is home to the narrow streets of the Old City and some of the Islamist militants' traditional bastions.