Iraqi cleric Moqtada Al Sadr, whose supporters are currently camped in the parliament building in Baghdad’s government complex, addressed the country on Wednesday, saying he did not want bloodshed but was “prepared for martyrdom”.
He also called for early elections, despite having gained the largest number of seats in October's national vote.
Mr Al Sadr withdrew his 73 MPs from Parliament last month to protest against what he said was corruption after 10 months of stalled talks to form the next government.
A rival coalition, the Iran-backed Co-ordination Framework, mounted a series of legal challenges against Mr Al Sadr and two allied Kurdish and Sunni parties, stymying attempts to follow the constitutional procedure to select a president, prime minister and Cabinet.
Iraq's Supreme Court later ruled that runner-up MPs could take the Sadrist bloc's seats, boosting the Co-ordination Framework's share of seats by 64.
Iraq’s Shiite elites have been working to de-escalate tension after the Co-ordination Framework organised a counter-protest against the Sadrist demonstrators near the parliament building and the house of caretaker prime minister Mustafa Al Kadhimi on Monday.
As both Mr Al Sadr and the Co-ordination Framework command powerful militias, the EU and UN have called for immediate de-escalation to avoid an intra-Shiite civil war.
Iraq's regular army is relatively neutral and security services on Monday struggled to keep the two sides apart.
On Tuesday, the UN mission to Iraq called for the country’s political rivals to hold talks aimed at finding a solution to the stalemate.
But Mr Al Sadr said it was not the time for negotiations and called on one of the Co-ordination Framework's leading figures, Hadi Al Amiri, who commands the Iran-backed Badr Organisation, to cut ties with his ally, former prime minister Nouri Al Maliki.
Mr Al Amiri has taken a different path to de-escalating the situation, meeting Mr Al Kadhimi on Wednesday evening and saying there was "no solution to the current crisis except sitting down and calling for dialogue".
On Wednesday, Mr Al Sadr said this "is not a struggle over power, rather a revolution".
He said he organised the recent protests for the sake of reform.
Mr Al Sadr's call for early elections could dismay Iraqis who have shunned national votes in increasing numbers, with turnout falling gradually since 2014.
Elections were held early in 2019, a key demand of a national protest movement against Iraq’s post-2003 political elite.