Advancing Iraqi troops have broken through Islamic State defence lines and have reached the edge of Mosul's eastern suburbs, the army says.
Troops of the Iraqi army's Counter-Terrorism Service (CTS) moved forward on Gogjali, an industrial zone on the eastern outskirts, after two weeks of fighting to clear surrounding areas of the insurgents.
The offensive to recapture Mosul is the largest military operation in Iraq since the US-led invasion that toppled Saddam Hussein in 2003, and it's now in its third week.
Commanders had warned earlier that the battle for the city, the hard-line militants' de facto capital in Iraq, could take weeks and possibly months.
The fighting ahead is likely to be more difficult as civilians still live there, unlike most villages taken so far by the Iraqi forces which were emptied of their Christian population.
A displaced woman carries bread she received from Barzani Charity Foundation (BCF) food at a camp on the outskirts of Erbil (Reuters)
Islamic State singled out religious minorities in northern Iraq, including Christians and Yazidis, for killing and eviction after leader Abu Bakr al-Baghdadi declared a caliphate in 2014 over territory they captured there and in neighbouring Syria.
Their seizure of Mosul and surrounding towns effectively drove Christians from the area for the first time in two millennia.
An Iraqi Christian soldier lights a candle during the first Sunday mass at the Grand Immaculate Church since it was recaptured from Islamic State (Reuters)
The recapture of Mosul would mark the militants' effective defeat in the Iraqi half of the territory they had seized.
It is still home to 1.5 million residents, making it four of five times bigger than any other city they controlled in both Iraq and Syria.
"The battle of Mosul will not be a picnic," Hadi al-Amiri, leader of the Badr Organisation, the largest Shi'ite militia fighting with Iraqi government forces, said from the southern frontline.
"We are prepared for the battle of Mosul even if it lasts for months."
Pro-Iranian Iraqi Shi'ite militias joined the fighting over the weekend, aiming to cut the route between Mosul and Raqqa, Islamic State's main stronghold in Syria.
They have also set oil wells on fire to cover their movements and displaced thousands of civilians from villages toward Mosul, using them as "human shields", UN officials and villagers have said.