Followers of an influential Shiite cleric have flocked to central Baghdad ahead of a scheduled parliament session to press for a vote on a new government.

Security forces blocked off all the roads leading to downtown Tahrir Square with razor wire and concrete blocks.

Thousands of Muqtada al-Sadr's supporters arrived there early on Tuesday to join others who have been holding a sit-in since two weeks ago, snarling traffic in huge parts of the Iraqi capital. Many protesters are waiving Iraqi flags and playing songs praising al-Sadr.

Prime Minister, Haider al-Abadi, has offered a new Cabinet but political blocs have rejected the nominees. A delay in the vote on a second list has also spurred a sit-in by lawmakers inside parliament, demanding top political leadership step down, including al-Abadi.