The Iraqi army and its allies have begun an offensive to drive fighters of the Islamic State of Iraq and the Levant (ISIL) group out of the most populated western area of Mosul.
Haider al-Abadi, the Iraqi prime minister, made the announcement during his appearance in Munich for an international security conference.
Just a month ago, Iraqi troops took control of the eastern side of Mosul, the last ISIL stronghold in Iraq.
The government forces are expected to target the city's airport first during this new phase.
It is located at the southern edge, to the west of the Tigris River, which divides the city.
Western Mosul is where the old city centre is located.
Commanders say the battle may prove to be more difficult than in the east, because tanks and armoured vehicles cannot pass through its narrow streets.
Fighters of ISIL, also known as ISIS, have also developed a network of passageways and tunnels that could aid their defence.
How challenging will the offensive be? And what will it take to regain full control of Mosul?
Presenter: Sami Zeidan
Ahmed Rushdi - director of the House of Iraqi Expertise Foundation
Judit Neurink - journalist based in Erbil and author of The War of ISIS: On the Road to the Caliphate
Source: Al Jazeera News