Iraq holds military parade to celebrate 'victory' over IS
Abadi on Saturday declared victory in Iraq's three-year war to expel the militant group that at its height endangered the country's very existence.
Iraqi army units marched through the main square in central Baghdad as helicopters and fighter jets flew overhead, witnesses said.
The parade was not broadcast live and only state media were allowed to attend.
Abadi had declared Sunday a public holiday after making his announcement, in which he said Iraq had defeated the extremisrs "through our unity and our determination".
Iraqis took to the streets to celebrate, including in the country's second city of Mosul and the capital, singing patriotic songs, waving the national flag and shouting "Iraq, Iraq!"
The militants of IS seized control of large parts of Iraq and neighbouring Syria in 2014, declaring a cross-border "caliphate" and committing widespread atrocities.
Backed by a US-led coalition, Iraqi forces gradually retook control of all territory lost to the militants over the past three years.
The head of the coalition on Sunday congratulated the Baghdad government for defeating IS, but warned that more work needed to be done to ensure the militants do not strike again.
"Much work remains, and we will continue to work by, with and through our Iraqi partners to ensure the enduring defeat of Daesh (IS) and prevent its ability to threaten civilisation, regionally and globally," Lieutenant General Paul E. Funk II said in a statement.
Experts warn that IS remains a threat, with the capacity as an insurgent group to carry out high-casualty bomb attacks using sleeper cells.
UN envoy Jan Kubis urged Iraqi people to build "a better future and common destiny for all in their united country with the same patriotism and determination that marked their nation's war against terrorism".
Saudi Arabia also congratulated Iraq on Sunday, with a foreign ministry official calling the militants' defeat "a grand victory on terrorism in the region", the official Saudi Press Agency reported.
Meanwhile, Abadi altered Saturday's statement in which he declared victory over IS to add a mention of the role played by the Kurdish peshmerga fighters, after complaints from the Kurdish authorities.
A statement from the autonomous Kurdish region had insisted on the "sacrifices" made by the peshmerga in the fight against the jihadists.
Meanwhile, Iraqi Interior Minister Qassem al-Araji told AFP that although "Daesh (IS) is finished militarily, there are still
some sleeper cells that we will track down and eliminate".
Iraqi militias involved in the fight against IS have been accused of committing numerous human rights abuses during the Mosul campaign.