Turnout hit a record low for parliamentary elections in war-scarred Iraq.
Sunday's vote was moved forward from 2022 as a concession to an anti-government protest movement that has demanded deep reforms in the oil-rich yet poverty-stricken country.
Prime Minister Mustafa al-Kadhemi brought forward the vote to appease a youth-led protest movement that erupted two years ago against graft, unemployment, and crumbling public services.
The premier and national spy chief tweeted that he had "kept his promise and done his duty by organizing fair elections".
The election was held under tight security in a country where key parliamentary blocs have armed factions and Islamic State group jihadists have launched mass-casualty suicide attacks this year.
Official provisional results were now expected until later Monday, but some candidates already claimed victory and celebrated with fireworks overnight in Baghdad and the southern city of Nassiriyah.