The release of Muslih without trial is one of the ways in which the government has not been successful in trying to seize power.
Iraq has released an Iranian-linked military chief who was arrested in May on terrorism charges after officials found sufficient evidence against him.
Two Iraqi officials say Qasim Mahmoud Muslih was released at 8am (05:00 GMT) on Wednesday.
His followers greeted him and kissed him at the center of Jadriya Bridge in Baghdad, taking pictures and videos to celebrate.
Muslih, from the holy city south of Karbala, was arrested on May 26. The military said the charges were related to terrorism but did not specify details.
He is the commander of the Forces (PMF) in Anbar province.
Security officials told Reuters news agency at the time that the arrests were linked to attacks by US troops stationed in Iraq. Some journalists and experts have blamed Muslih for his alleged involvement in the killings.
Iraqi Prime Minister Mustafa al-Kadhimi has publicly stated his opposition to Iran’s military and allied forces, and Muslih’s arrest was a major attempt to restore order.
His release without trial is a challenge to the cause and one of the attempts failed to seize the troops.
Two anti-Iranian-backed groups – the arrest of Muslih and the June 2020 arrest of alleged rocket fighters against U.S. forces – did not lead to a verdict and all the detainees released.
On both occasions, armed militiamen entered the peaceful area of Baghdad, where foreign diplomats and government buildings threatened al-Kadhimi.
After Muslih’s arrest, al-Kadhimi held a meeting with key Shia leaders to end the atrocities. Based on what the meeting did, Muslih was arrested at the hands of the PMF.
An investigation committee comprised of officials from the Ministry of Defense and Interior, National Security and the PMF was set up to look into the matter. Muslih was in the custody of the Joint Operations Command at the time. The JOC oversees several Iraqi security forces.
On Monday, his file was sent to the PMF investigating judge, who ordered his release.