In Baghdad, security was tight as dozens of army cadets wearing anti-Covid masks and gloves lined up at a polling station set up in a school, after voting got underway at 7:00 am (0400 GMT).

More than one million security force members are able to vote on Friday in the locations where they are stationed, because voting in their home regions -- as other citizens will do -- could prove challenging for those in distant locations.

But the 160,000 members of the powerful Hashed al-Shaabi are ineligible for early balloting. They have to wait until Sunday, drawing criticism from the network of mainly Iran-backed former paramilitary groups, after the electoral commission said Hashed officials had not provided lists of fighters for the special vote.

Also casting ballots Friday are around 120,000 displaced people, some of them living in 27 camps, and more than 600 prison inmates.

Iraq's election is being held a year early in a rare concession to a youth-led protest movement that broke out in 2019 against a political class widely blamed for graft, unemployment and crumbling public services.

The movement was violently suppressed, and an overwhelming majority of those who took part have decided to boycott the election, which they say is being held in an undemocratic climate.

In recent months, dozens of the movement's activists have fallen victim to a wave of assassinations and kidnappings that have been blamed on pro-Iranian groups.

Analysts say the same parties will continue to hold the balance of power after the vote.

More than 3,240 candidates are in the running.