Iraqi security forces have been deployed on the streets of Basra, a day after protesters in the city stormed the Iranian consulate and torched government buildings.
The violence has rocked the oil-exporting Shiite heartland and sparked alarm across a conflict-weary country.
Masked troops in combat fatigues set up checkpoints and rode through the city centre in black pickup trucks with heavy weapons mounted in the back.
Security forces in Humvees deployed at intersections.
The deployment came after an alliance of powerful Shiite militias, many of them backed by Iran, vowed to respond to the violent protests that have gripped the city for the past week, raising the threat of further violence.
At least 15 people were killed and 249 injured in clashes between protesters and security forces this week, health officials say.
Since June, Basra has been shaken by the most serious protests in the oil-rich southern region in years, with angry residents complaining of poor public services.
In recent days, protests escalated, as crowds turned their rage on neighbouring Iran, blaming its outsized influence in Iraq’s political affairs for their misery and calling for radical change.
Iran controls powerful Shiite militias in Basra, home to some of the largest oil fields in Iraq.
Raad Abdelhamid, a Basra firefighter, said he feared for Iraq.
“The militias are responsible for this corruption,” he said as he stood outside the still-smouldering provincial government building on Saturday, his second day of working to put out a fire there.
“I fear Basra is headed for more blood,” he said, in tears.
A banner on one side of the building read in Arabic: “No to the militias, your militias under our feet.”
Despite the oil wealth, the city has long suffered from government neglect, soaring unemployment and a crumbling infrastructure.
Over the past month, thousands of people were taken to hospital after drinking polluted water.
Angry protesters have torched government buildings and offices belonging to the Iranian-backed militias in the weeklong protests demanding improved services and an end to corruption.
On Friday night, protesters chanting anti-Iranian slogans including “Iran, out, out!” stormed the Iranian consulate and set it on fire.
They also burned an Iranian flag and trampled on a portrait of Iran’s Supreme Leader Ayatollah Ali Khamenei.
Iran’s Foreign Ministry spokesman, Bahram Ghasemi, condemned the attack on the consulate, which he said caused significant damage to the building.
He called for maximum punishment for the assailants. The ministry also summoned the Iraqi ambassador to relay Tehran’s “strong protest”.
On Saturday, an Iraqi flag was placed at the entrance to the consulate after the Iranian one was torn down and set ablaze.
Sprayed in red on the concrete wall of the consulate were the words: “Down with Iran, down with the militias, the revolution will continue.”
The government-sanctioned Shiite militias known as the Popular Mobilisation Forces — Hashed in Arabic — threatened retaliation Saturday, raising the spectre of further escalation.
“We will have a response to those who are carrying out acts of arson and sabotage,” the militias’ commander, known as Abu Yasser al-Jaafari, told reporters in Basra.
On Saturday morning, assailants fired three Katyusha rockets at Iraq’s Basra airport, which houses the US consulate, adding to the tensions.
Security officials said they reopened partially the vital Umm Qasr port on the Persian Gulf on Saturday, after shutting down operations for several days amid concerns that protesters might try to storm it.