Hundreds of protesters have stormed the Iraqi Prime Minister's office, it has been reported.
Eye witnesses have reported tear gas and gunshots have been fired. One person has reportedly been shot in the head.
The major security breach has occured in Baghdad's Green Zone which is thought to be one of the most secure areas in the country.
In a news flash on state television, the military announced a curfew is being imposed in the capital city "until further notice."
The incident follows a similar mass protest last month when hundreds of people stormed Iraq's parliament buildings. Supporters of the Shia cleric Muqtada al-Sadr forced open the gates of the protected Green Zone in Baghdad to demonstrate against government deadlock. A state of emergency was subsequently declared in the city.
Mr Sadr and his supporters have called for Prime Minister Haider al-Abadi to follow through on promises of reform, including anti-corruption measures, which he says have not yet materialised.
More than 200 people have died in a string of bomb attacks over the course of the last week, further erroding confidence in Mr Abadi's premiership. Mr Sadr said that attacks proved Mr Abadi was not providing sufficient stability for the country, saying the attacks: "are the clearest evidence that your government has become unable to protect and provide you with security."
