Iraq’s Prime Minister Mustafa Al Kadhimi has made several bold actions to curtail militias since assuming office last May – raiding paramilitary groups' headquarters in Baghdad and arresting a prominent armed leader and dozens of fighters. Mr Al Kadhimi vowed to rein in militias, known as the Popular Mobilisation Forces (PMF), that operate outside of the state control. But, his ability to operate against the powerful groups is limited. The PMF is the group of state-sanctioned militias formed to help Iraq’s army defeat ISIS in 2014. Among the most powerful members of the group are Iran-backed Shiite militias that are known to carry out directives from Tehran. Since the assassination of top Iranian general Qasem Suleimani in January 2020, attacks on American interests in Iraq have increased considerably. They include the targeting of Iraqi military bases hosting foreign troops, the US Embassy in Baghdad and US oil companies. Iraq, US and British military personnel have been killed and injured during the attacks. Washington has blamed Iran-backed militia group Kataib Hezbollah for orchestrating attacks against its embassy and American troops inside Iraqi bases and criticised the Iraqi government for not identifying and arresting the culprits. Shortly after Mr Al Kadhimi took office, security forces arrested 14 members of the PMF faction Kataib Hezbollah. But, after threats of escalating violence from the group – one of the most powerful – the men were released. The incident showcased Mr Al Kadhimi's struggle to assert the rule of law and rein in powerful groups. It was the government’s first raid against the militias accused of conducting rocket attacks against the US presence in the country. Washington has pressured Baghdad to take tougher action against the group. It even warned officials that it will shut down its embassy inside the capital’s heavily fortified Green Zone. Government moves against prominent PMF leader In an unannounced move last Wednesday, Iraqi authorities arrested Qassem Musleh, a senior leader of the PMF’s operations in Anbar. His arrest was over links to terrorism and the assassinations of civil society activists, journalists and protesters, the government said. Mr Musleh is currently being questioned by a joint investigation committee and has not been released, according to several government officials. This is the first time Iraq attempts to arrest a senior PMF official and the fact that the government has managed to keep him in custody for nearly a week is significant, Sajad Jiyad, a Baghdad based fellow with the Century Foundation said. "Despite pressure from PMF, the government is still investigating to find evidence into what Musleh has done and maybe charge him or take him to trial," Mr Jiyad told The National. As well as heading operations in Anbar, where the US has troops, Mr Jiyad said that Mr Musleh is also one of the men who controls the Iraq-Syria border and has clashed with other groups over access. "Musleh has not been charged yet and is under arrest. We will have to see if there are any charges that will come – they can't hold on to him indefinitely and we will find out if there's enough evidence to charge him," he said. Being able to hold the key figure and bring criminal charges will make the government look stronger. Mr Jiyad said. After last Wednesday’s arrest, tensions in the capital skyrocketed with PMF fighters taking to the streets around Mr Al Kadhimi’s office. Iraqi security forces and the elite Counter-Terrorism Service deployed to protect the government and diplomatic missions, sparking fears of violence. Some armed PMF factions gathered at the entrance to the Green Zone. Mr Al Kadhimi described the show of force as “a serious violation of the Iraqi constitution and the laws in force." “We have directed an immediate investigation into these movements,” he said. The arrest of Mr Musleh was made after a return of anti-government protests in the capital and across the south following the targeted killing of activist Ihab Al Wazni in the southern city of Karbala last month. More than 70 activists have been kidnapped or killed since a protest movement erupted in October 2019 against government corruption, foreign interference and poor job prospects. Protesters gathered around Baghdad's Tahrir Square last Tuesday shouting slogans against Iran-backed militias, many of whom are suspected of being behind the killings, and carried pictures of the victims.