After Sadr made the announcement on Monday, his loyalists stormed a government palace and clashed with rival groups.
After nightfall, machine gun fire and explosions could be heard, the sky of Baghdad's Green Zone lit up by tracer light, Reuters reported. The headquarters of Iraq's ministries and foreign embassies are located in this green zone. The Iraqi capital witnessed the deadliest fighting in years this night.
After Sadr announced that he would withdraw from all political activities and retire, violence continued throughout the day, followed by rival fights with his followers at night.
Sadr said he took this decision in view of the failure of other Shiite leaders and parties to reform a corrupt and decaying regime.
Sadar later said that he would go on a hunger strike to protest against the use of arms by all sides.
Iraq is struggling to recover from decades of war, sanctions, civil strife and corruption. Meanwhile, the continuing deterioration of the political stalemate between Sadr and his Shiite Muslim rivals (mainly backed by Iran) pushed the country back into conflict.
Shia leader Muqtada al-Sadr is leaving politics in Iraq
Iraqi groups have been engaged in sectarian conflict since 2003, and have recently become embroiled in inter-sectarian, inter-ethnic political rivalries.
The latest violence pits Sadr's supporters (including a heavily armed militia) against rival Iranian-backed paramilitaries and security forces.
Sadr's coalition won a majority of seats in Iraq's national elections in October last year. He then tried to form a government by leaving out Iran-backed groups. But due to political deadlock, he could not form the government.
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