Three government ministers backed by ousted Iraqi parliament speaker Mohammed Halbousi will resign their positions in protest of a ruling by Iraq's top court to terminate his tenure on Tuesday, a statement by Halbousi's Taqaddom party said, News.az reports citing Reuters.

Slamming the court decision as "blatantly unconstitutional" and "clear political targeting," the party also said it would boycott meetings of the ruling State Administration Coalition, while its lawmakers would boycott parliament sessions.

The Iraqi Federal Supreme Court's surprise decision upended the career of Iraq's most powerful Sunni Muslim politician and sets the stage for a fight over succession.

Resignations by the country's planning, industry and culture ministers also destabilizes the government of Prime Minister Mohammed Shia al-Sudani, who came to power one year ago backed by a coalition that is led by a group of Shi'ite Muslim parties but also includes Sunni Muslim Arabs and Kurds.

State media said the court decision, which is final and not subject to appeal, was related to a Federal Supreme Court case brought against Halbousi earlier this year, without elaborating.

Local media, lawmakers and analysts said the decision was related to alleged forgery on the part of Halbousi. Halbousi's office could not be reached for comment.

Re-elected in 2021, Halbousi was serving his second term as speaker, a post he assumed in 2018 and which, under the sectarian power-sharing system established after the 2003 U.S. invasion, is the highest office reserved for a Sunni Muslim.

Under the governing system in place since the post-Saddam Hussein constitution was adopted in 2005, the prime minister is a member of the Shi'ite Muslim majority, the speaker is a Sunni and the largely ceremonial role of president is held by a Kurd.

This sectarian formula has often come under heavy strain as a result of competing agendas and has divided the spoils of massive oil wealth between powerful factions while failing to prevent bloodshed or provide people with basic services.