Police in Basra raided the headquarters of an Iran-backed militia accused of shooting at protesters in the Iraqi city.
A statement from Prime Minister Mustafa Al Kadhimi's office said security forces on Monday morning stormed a building from which live bullets were fired at the demonstrators. Members of the militia were arrested, weapons and ammunition were confiscated and an investigation into the shootings was launched.
Those arrested "were referred to the judiciary for a fair retribution", the statement said.
The militia group, named Thar Allah or God's Revolution, was established in 1995 and has been described as a "threat to Iraq's stability".
Crowds in the city rallied on Sunday night as people demonstrated outside the militia's office, days after the formation of a new government last week.
One protester was killed and four injured as they called for the resignation of the local government, Ali Al Bayati, a member of the Iraqi Human Rights Commission said.
"They attacked security forces guarding public and political offices with stones and were met with live ammunition," Mr Al Bayati told The National.
“The protesters accused some military group of targeting them and for this reason, security forces detained some of them today,” he said.
Angry Basra residents have repeatedly taken to the streets in recent years to protest failing government services, including water contamination, corruption and lack of employment opportunities.
The events in Basra reflect the role and influence of the militias, which played a major role in retaking Iraqi territory from ISIS.
Mr Al Kadhimi said on Monday that his government was sticking "to its promises of respecting human rights, the right to a peaceful demonstration, to protect demonstrators and to hold perpetrators accountable".
Activists have continually said the Iranian-backed militias that control Iraq’s oil capital of Basra are waging a campaign of intimidation and arbitrary arrests to silence protests aimed at poor government services and Tehran’s growing influence in the region.
"The new government needs to work on reassuring the protesters that they will stop the intimidation campaigns against them, hold perpetrators to account and offer reparation for victims or their families," Mr Al Bayati said.
Protesters first took to the streets in the country in October, but the movement waned amid a political deadlock after the resignation of Adel Abdul Mahdi and the coronavirus pandemic.
In the first four months of the revolution, security forces and Shiite militias were behind the killing of more than 500 protesters but dozens were also kidnapped by armed gangs.
However, few arrests were made. Monday’s arrests came after Mr Al Kadhimi extended an olive branch to protesters who are demanding jobs, public services and an end to decades of corruption and mismanagement in the oil-producing nation.
Mr Al Kadhimi is trying to reverse some of the damage done by the previous prime minister Adel Abdul Mahdi, by trying to win back trust and confidence from protesters, Sajad Jiyad, a Baghdad-based analyst said.
"He's trying to show that the government is going to uphold the rule of law and it's willing to show some accountability for past abuses and going forward that protesters should not face violence from government forces," Mr Jiyad told The National.
Over the weekend, Mr Al Kadhimi announced a plan to release protesters not involved in lethal violence who had been arrested since October. On Sunday, the judiciary moved to fulfil the order, although there was no indication anyone has yet been released.