Iraqi Security Forces began the second phase of their offensive against Islamic State Militants in Mosul, pushing from three directions into eastern districts where the battle has been deadlocked for nearly a month.
In the northern front heavy gunfire was audible and a suicide car bomb was disabled by the Iraqi Army before reaching its target.
State TV said Islamic State defences were collapsing in several areas.
The military has not entered the city’s western side, whose built-up markets and narrow alleyways dating back more than two millennia will likely complicate advances.
Since the offensive to capture Mosul began 10 weeks ago, counter-terrorism forces have retaken a quarter of the city, the militants’ last major stronghold in Iraq.
However their advance has been slow and troops on other fronts have made little progress.
The operation has been slowed by concern to avoid casualties among civilians, who despite food and water shortages have mostly stayed in their homes.