Hundreds of Iraqi protesters stormed into parliament in Baghdad on Saturday demanding reforms, after breaching the heavily fortified Green Zone that also houses several foreign embassies.
The protesters, who are followers of influential Shiite cleric Moqtada al-Sadr, pushed their way into the parliament building, witnesses said.
They moved in shortly after parliament adjourned a meeting to vote on a new government proposed by Prime Minister Haider al-Abadi.
The breach prompted authorities to close all access roads to Baghdad in order to prevent protesters across Iraq from streaming into the capital, a police official said.
"Only departures are allowed from the capital," the official said on condition of anonymity, adding that security has been tightened around the central bank and other major banks in the city.
Private television station al-Ahed reported that the prime minister has moved from his office in the Green Zone to an undisclosed place outside the area for safety reasons. There was no official confirmation.
TV footage showed the protesters waving the national flag inside parliament, chanting "peaceful" and "Iraq is not for sale."
Some demonstrators were also seen atop the building.
"Security forces did not block our way," a protester said.
"All parliamentarians escaped from the place on seeing us," he added.
Some demonstrators vowed to stay inside the assembly until the long-awaited reforms are implemented.
The breach followed al-Sadr's criticism, in a televised address Saturday, of delay in implementing reforms he said were necessary to fight corruption.
Under pressure from street protests and religious clerics, al-Abadi is trying to form a new government of independent technocrats. But major political blocs in parliament have thwarted the move in recent weeks.
On Tuesday, the assembly approved some members of the proposed government nominees.
Iraqi governments have been formed along political and sectarian lines since the US-led 2003 invasion that deposed Saddam Hussein. Critics say the system contributes to corruption.
Al-Abadi has warned that the current crisis can hamper the country's US-backed fight against Islamic State, which controls key areas in Iraq's Sunni heartland.