Anti-government protesters carry an injured man in Baghdad on May 20. (Khalid Al-Mousily/Reuters)

Security forces used live ammunition and tear gas to push back protesters who broke into the fortified Green Zone on Friday, in a sharp escalation of unrest that has gripped the Iraqi capital.

Iraq’s military imposed a curfew across Baghdad after the protesters breached the secured area, which is home to the parliament and other government buildings. After protesters broke through — reaching the office of Prime Minister Haider al-Abadi — security forces could be seen advancing across the bridges that lead out of the Green Zone and firing tear gas as gunshots rang out, though it was unclear if they were aiming live ammunition directly at the crowd.

Hospital officials said at least 617 people were injured, largely from inhaling tear gas. They did not report any deaths or injuries from gunfire.

The turmoil is destabilizing the capital amidst the country’s fight with Islamic State militants, with fears the group could try and capitalize on the unrest to launch attacks on Baghdad, where it has carried out a wave of attacks in recent days.

The violence also further undermines the authority of Abadi, who is already politically weak and therefore struggling to enact the reforms demanded by protesters. An economic crisis due to a crash in oil prices also is adding to the pressure.

“We were holding roses and flags,” said Haider Hashm, 40, sitting on the curb of a bridge to the Green Zone and struggling to speak because of the effects of tear gas. “But while we were giving them roses, they gave us tear gas and bullets.”

It marked the second time in a month that protesters have broken into the restricted zone in the heart of the capital, an area usually out of bounds for Iraqis who don’t hold passes. But while the first breach was largely peaceful — despite protesters entering parliament and hitting lawmakers — this time security forces fought back.

Tear-gas canisters flew through the air and a constant crack of gunfire rang out as forces mandated with ensuring security in the Green Zone pushed the demonstrators back over bridges leading to the area. The military said that an unspecified number of members of the security forces had been stabbed.

As the crowds surged out, a steady stream of ambulances were still screeching in.

“We stormed them like the Palestinians storm the Israelis,” said Mehdi al-Rubai, 26, as he left the area. “They are animals; they are shooting bullets at us.”

Fadhil al-Shuwaili, a member of the health committee on Baghdad’s provincial council, said three people had been confirmed killed: one by a gunshot to the head, one by a gunshot to the stomach and another who suffocated. That claim could not be verified.

Despite efforts by the security forces to stop protesters, some clambered over blast walls to get into the Green Zone. They posted pictures of themselves inside the prime minister’s office on social media sites.

The Green Zone, also known as the International Zone, is the location of the U.S. Embassy, where extra Marines had been made available for its protection after demonstrators came close to its gates last month.

“We are aware protesters entered the International Zone,” said State Department spokesman John Kirby. “We will continue monitoring the situation closely.”

The previous breach was an embarrassment for Abadi, and in its aftermath the premier sacked the head of Green Zone security and vowed to arrest those who had assaulted lawmakers and broken property. But he is no closer to meeting the protesters’ demands for reform; he has not even managed to gather enough lawmakers for parliament to reconvene, necessary in order to legislate any changes.

The demonstrators are largely supporters of Shiite cleric Moqtada al-Sadr, who has ratcheted up political tension in the country by calling for a new technocratic government and urging his followers to the street. Meanwhile, anger has boiled in his support base of Sadr City, where there have been two bombings in the space of a week. Analysts speculated that the Islamic State was attempting to provoke Sadr’s followers as a way to cause unrest, turning their anger on the government for not protecting them.

As night fell, the crowds had been largely dispersed.Rows of Humvees could be seen on bridges around the capital, while Baghdad Operations Command said forces from the country’s elite Golden Division had been deployed to protect the Green Zone. Police carrying batons patrolled the streets.

More than 250 were injured, according to Ali Mohsen al-Tamimi, the governor of Baghdad, who is with Sadr’s party. Some were critically injured by live ammunition, he said.

In a statement, Sadr said that the government had used tear gas and live fire on “unarmed protesters.”

“Be patient, heroic Iraqi people, your peaceful revolution will end with victory,” he said.

Carol Morello in Brussels contributed to this report.

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