Supporters of Iraqi Shia leader Muqtada al-Sadr have erected tents and prepared for an open-ended sit-in at the country’s parliament in Baghdad, in a move that could prolong political deadlock.

Thousands of people had stormed into the fortified Green Zone on Saturday, taking over the empty parliament building for a second time in a week. Their demands include early elections and constitutional amendments, among others.

Al-Sadr has not visited the scene, but in a tweet on Sunday, he said the sit-in was “a great opportunity to radically challenge the political system, the constitution, and the elections”. He called on all Iraqis to join the “revolution”, an indication the sit-in will likely become a drawn-out event.

Nearly 10 months after the elections, the country is still without a new government due to the repeated failure of negotiations and the en masse resignation last month of al-Sadr’s bloc, the largest in parliament.