Thousands of Iraqis protested in the capital and in southern Iraqi cities on December 22 ahead of a midnight deadline to pick an interim prime minister, saying the current nominee is too friendly with Tehran.
Iraq's constitution says the largest bloc in parliament should name a new candidate for prime minister within 15 days, a deadline that has already been postponed by three days.
The protesters, who reportedly closed roads in oil-rich Al-Basrah and other southern regions, object to nominee Qusay al-Suhail, who served as education minister in the last government.
At least 400 people have died in politically charged violence since protests erupted in early October over official corruption and a lack of jobs, as well as frustration with the political system in place since the 2003 U.S.-led invasion.
There was no major violence reported in the December 22 demonstrations.
But some schools and state institutions were closed as part of the protests.
The outgoing prime minister, Adil Abdul-Mahdi, was forced by public pressure and a senior cleric's withdrawal of support to resign in late November.
He is expected to remain atop a caretaker government until there is a replacement named.
Iraqi governments have routinely been set up along sectarian divides and fractured amid public outrage over perceived incompetence.
A debate still rages over which bloc has the most seats in Iraq's parliament, with lawmakers sometimes changes alliances, despite efforts by President Barham Saleh and the Federal Supreme Court to press for clarity.