Leading Iraqi Shi'ite clerics are calling for the disbandment of powerful Iran-backed Shi'ite militias now that the nation has retaken its second-largest city, Mosul, from the Islamic State extremist group.

Muqtada al-Sadr, an anti-American firebrand with a large following among Baghdad's urban poor, on August 4 called for the disbandment of Hashed al-Shaabi, a paramilitary organization with an estimated 122,000 troops dominated by Iran-backed Shi'ite militias.

Sadr was speaking to thousands of supporters in Baghdad after a rare visit over the weekend to Iran's archrival Saudi Arabia, where he met with the Saudi crown prince.

In a speech broadcast on huge screens, Sadr urged Iraqi Prime Minister Haidar al-Abadi to dismantle the Hashed militias, or Popular Mobilization Forces, and "integrate into the army the disciplined members," AFP reported.

Sadr also called on the authorities to "seize the arsenal of all armed groups."

Sadr himself led a militia that fought against the U.S. occupation of Iraq in the last decade. But he is now seen as a nationalist who has repeatedly called for protests against corruption in the Iraqi government.

Another leading cleric calling for the disbandment of the Iran-backed militias is Shi'ite Sheikh Fadil al-Bidayr, who was one of the religious leaders who issued an urgent call to arms answered by the militias in 2014 when IS swept through northern and western Iraq and captured Mosul amid a collapse in the Iraqi Army.

"We always knew that Iran would use this [call to arms] to increase its own power in Iraq, but we had no other choice" at the time, Bidayri told AP.

Bidayri said that now that Mosul has been retaken and the Iraqi military has been partially rebuilt, he believes the Shi'ite militias should be disbanded, to curb Iranian influence in Iraq and reduce sectarian tensions.

The elderly sheikh, like much of Iraq's religious establishment in Najaf, is a staunch nationalist and wary of Iran's growing influence.

"From the very beginning...Iran used every opportunity to get involved in Iraq," he told AP. "Each time they used the protection of the Shi'ite people as an excuse."

The Hashed al-Shaabi is the largest Shi'ite paramilitary group and is nominally under Abadi's command. But some of its components have for years been sending fighters to support Syria in its six-year civil war with rebel groups.

The paramilitary force took part in the battle to liberate Mosu, and could join future operations aimed at routing the militants from areas of the country they still hold. IS still controls parts of western Iraq, including much of the desert province of Anbar.

While Sadr, Bidayri, and some other Iraqi political, religious, and military leaders say the Shi'ite militias must go, militia leaders say their sacrifices on the battlefield have earned them a permanent place in Iraq's security forces.

Although the Shi'ite militias did not play a central role in the battle to retake Mosul, they moved into the deserts held by IS west of the city, massing around the town of Tal Afar and retaking a border crossing between Iraq and Syria.

They also took control of highways bisecting the Sunni heartland in western Iraq and used as vital military and civilian supply lines.

In past fights against IS, including the operation to retake the cities of Tikrit and Fallujah, the Shi'ite militias were accused of sectarian killings and other abuses against minority Sunnis. Militia leaders acknowledged some abuses occurred but said those responsible have been disciplined.

"The Hashed will remain...and our relationship with Iran will remain," Hadi al-Amiri, a senior leader of the Badr Brigade, one of Iraq's most powerful Shi'ite militias, told AP.

Amiri said IS's insurgent capabilities will pose a long-term security threat to Iraq and his forces will have a continuing mission.

Iraq's prime minister has also repeatedly said he backs the Popular Mobilization Forces, telling reporters at a press conference last week that they "must remain at least for years, as the terrorism threat still exists."

Moreover, analysts say it's unlikely Iraqi security forces would be able to absorb all the militia factions.

With reporting by AP, AFP, and Reuters