A curfew has been imposed on the Iraqi capital, Baghdad, after security forces opened fire on protesters who had entered the city's heavily fortified Green Zone and entered at least one government building.
Witnesses said dozens of people were injured from tear gas and live fire in the clashes.
The protesters included supporters of powerful Shia Muslim cleric Moqtada al-Sadr and people from other groups who are displeased with the government's failure to approve anti-corruption reforms and provide security.
A Reuters witness said the protesters were stopped at the gate of the cabinet building but witnesses later said they had entered.
Unverified online photos showed protesters holding Iraqi flags and flashing peace signs in front of the insignia of the prime minister's press office and inside a meeting room.
The protesters began withdrawing from the Green Zone to Tahrir Square, but witnesses said an Interior Ministry force and unidentified gunmen opened fire there.
State television said Baghdad Operations Command was imposing a curfew in the capital "until further notice."
Mr Sadr supporters protesting parliament's failure to approve a non-political cabinet also stormed the Green Zone on 30 April in an unprecedented breach of the central district, which houses parliament, government buildings and many foreign embassies.
They have added to their grievances the government's failure to provide security after a wave of bombings claimed by the so-called Islamic State group in the Iraqi capital this month which killed more than 150 people.
Mr Sadr did not explicitly call for today's demonstration.
Iraq's political crisis broke out in February, when Prime Minister Haider al-Abadi announced plans to appoint a cabinet of independent technocrats, threatening to uproot a system of political patronage that makes the public administration open to corruption.
He has warned that the impasse could hamper Iraq's fight against IS, which continues to control territory in northern and western Iraq.
Mr Sadr, the heir of a revered clerical dynasty, says he backs Mr Abadi's plan and has accused other political groups of blocking the reforms due to their own vested interests.
