Muslih’s release is one of several unsuccessful government attempts to crack down on armed groups without prosecution.
Iraq has released an Iran-aligned armed group commander who was arrested in May on terrorism-related charges after authorities found insufficient evidence against him.
Two Iraqi officials said Qasim Mahmoud Muslih was released at 8 a.m. (05:00 GMT) on Wednesday.
His supporters greeted him with hugs and kisses on Baghdad’s central Jadriya Bridge, taking photos and videos with him to celebrate.
Muslih was arrested on May 26 from the southern holy city of Karbala. The army had said the allegations were related to terrorism, but did not give details.
He heads the Popular Mobilization Forces (PMF) in Anbar Province.
Security officials told Reuters news agency at the time that the arrests were linked to attacks on US forces stationed in Iraq. Some media and analysts said this was due to Muslimah’s alleged involvement in the killing of peaceful pro-democracy activists.
Iraqi Prime Minister Mustafa al-Kadhimi has publicly placed himself in opposition to Iran-backed militias and parties, and Muslih’s arrest was a major attempt to rein in his power.
His release without prosecution is a setback to those efforts and one of several failed attempts to crack down on armed groups.
The two most high-profile moves against Iran-backed groups – the arrest of Muslih and the detention of fighters allegedly involved in rocket fire against US targets in June 2020 – each resulted in no trial and the release of all those arrested been done.
On both occasions, heavily armed militias stormed Baghdad’s fortified Green Zone, where foreign embassies and government buildings are located, threatening al-Kadhimi.
After Muslih’s arrest, al-Kadhimi held meetings with prominent Shia leaders to suppress hostilities. Based on the outcome of the meeting, Muslih was taken into the custody of the PMF.
An investigative committee consisting of officials from the ministries of defense and interior, national security and the PMF was set up to look into his case. Muslih was in the custody of the Joint Operations Command during that time. The JOC oversees a range of Iraqi security forces.
On Monday, his file was sent to an inquiry judge of the PMF, who ordered his release.