Iraq has declared victory over the Islamic State terror group in Mosul after months-long campaign, dealing the biggest defeat yet to the jihadist group. <br/><br/>Prime Minister Haider al-Abadi's office said he is in liberated Mosul to congratulate the heroic fighters and the Iraqi people on the achievement of the major victory, three years after IS declared its self-styled caliphate from the city. The victory comes at an enormous cost. <br/><br/>Much of Mosul is in ruins, thousands dead and wounded, and nearly a million people were forced to leave their homes. Prime Minister's office said Abadi held meetings with commanders in Mosul and issued a series of commands on sustaining victories and eliminating the defeated remnants of IS, as well as establishing security and stability in the liberated city.<br/>'<br/>A US-led coalition launched military operations against IS in Syria and Iraq in mid-2014, carrying out waves of air strikes against the jihadists and sending advisers to work with local ground forces.<br/>'<br/>French President Emmanuel Macron, whose country is a key part of the coalition, was among the first world leaders to offer his congratulations.<br/>