Following ten days of relaxed fighting, the Iraqi federal police took a major role in the second phase of the offensive, with a morning attack on the city's south-east.
The manoeuvre was co-ordinated with separate attacks from the city's north and south, supported by coalition airstrikes.
"The attack is currently engaged on three fronts at the same time," said Brigadier General Mohammad Hatem.
"This time, we are trying to absorb the effects of IS' suicide attacks with a new battalion of Brahms armed tanks at the front."
American forces are providing support through air-strikes and the presence of Apache helicopters.
Specialist Iraqi counter-terrorism forces advanced on the eastern neighbourhoods of al Quds, al-Karamah and Sina in the early hours of the morning and were met with heavy shelling from IS positions.
|Counter-terrorism forces, advised by US command, also made a strong start in the Intisar neighbourhood before being met by strong resistance.|
Counter-terrorism forces, advised by US command, also made a strong start in the Intisar neighbourhood before being met by strong resistance.
"Our troops now are advancing. In the first five or 10 minutes they took 500 meters. Just now they are starting to shoot," an anonymous officer told Reuters.
The battle for Mosul is one of the largest ground operations in Iraq since the 2003 US-led coalition invasion to topple the Saddam Hussein.
American forces are reportedly now becoming more involved in the direction of the Mosul offensive, with more military advisors now positioned at decision-making control centres in the city itself.
Coalition airstrikes bombed the last remaining bridge connecting the east and west of Mosul on Monday in a bid to prevent IS suicide bombers from accessing government positions.
"The enemy is currently isolated inside the left (eastern) bank of Mosul," said Yahia Rassol, a military spokesman.
"In the coming days, Iraqi forces will liberate the entire left bank of Mosul and after that we will tackle the right."
IS captured Mosul in the summer of 2014, when it swept across much of northern and central Iraq, and the group’s leader declared the establishment of its self-styled caliphate from the pulpit of a Mosul mosque.
The city is still home to around a million people. Some 120,000 have fled since the operation began on Oct. 17, according to the United Nations.
With input from AP