Experts speaking with Diyaruna said the Iraqi militia group Kataib Hizbullah, affiliated with the Islamic Revolutionary Guard Corps (IRGC), has a significant role in pushing the IRGC agenda forward in Iraq.
The group is considered to be Iran's "favoured proxy", they said, and "the most rebellious against the authority of the Iraqi state".
Despite being an influential part of the Popular Mobilisation Forces (PMF) -- which ostensibly answers to the Iraqi government -- Kataib Hizbullah refuses to obey the orders of Iraq's Commander in Chief, Prime Minister Mustafa Kadhemi.
The militia has also been accused of being behind missile attacks on embassies, foreign military missions and civilian homes.
Political activist and al-Muwatana party leader Ghaith al-Tamimi told Diyaruna that Kataib Hizbullah and other militias are "IRGC tools" led directly by the Quds Force, IRGC's overseas arm.
"IRGC-backed militia groups seek to isolate Iraq," he said.
These groups try to obstruct Baghdad's efforts to establish security and economic development, he said.
'Most loyal IRGC servant'
Iran's IRGC manages its proxies in Iraq, which ultimately harms Iraq's stability, economy and foreign relations, al-Tamimi said.
Since its inception in April 2007 by slain Quds Force commander Qassem Soleimani, who was killed in a US raid in January along with senior PMF official Abu Mahdi al-Muhandis, Kataib Hizbullah has received weapons from the IRGC, as well as training from Lebanese Hizbullah, with which it maintains close ties.
Kataib Hizbullah assumed its present form when five armed factions active since 2003 -- Kataib Abu al-Fadl al-Abbas, Kataib Karbala, Kataib al-Sajjad, Kataib Zeid Ibn Ali and Kataib Ali al-Akbar -- joined forces.
It currently boasts some 10,000 members, most of whom are in Iraq and some in Syria. It also has affiliates such as Usbat al-Thaereen, a group it uses as a smokescreen for its strikes on Baghdad's Green Zone.
"Kataib Hizbullah's influence has increased since 2017. It can be described as the most loyal IRGC servant," political analyst Alaa al-Nashou told Diyaruna.
The militia has turned into an influential force within the PMF, notably within its intelligence and security departments. It also has control over a number of affiliated militia groups, he said.
According to al-Nashou, Kataib Hizbullah controls the Missiles Directorate, where Iran reportedly provides it with ballistic missiles to store at the group's main base in Jurf al-Sakhr, and trains it on manufacturing this technology.
The current PMF chief of staff Abdul Aziz al-Mohammadawi, known as Abu Fadak or "Khal" (uncle), is also a Kataib Hizbullah leader. He was chosen to succeed al-Muhandis.
Kataib Hizbullah, which has been on a global terrorism watchlist since 2009, also spreads propaganda through media outlets, satellite TV channels and religious and cultural centres in Iraq, which help spread Iran's Wilayat al-Faqih doctrine (Guardianship of the Jurist).
Al-Nashou said the militia poses significant danger to Iraq's interests and stability, as well as the security of its citizens.
It is the IRGC's main tool to weaken Iraq so that the Iranian regime "can get closer to its dream of regional hegemony", he said.
It is constantly trying to portray itself as a group that is above the law by virtue of its strong connection with the Iranian regime, he said.
Kataib Hizbullah had a role in forcibly stopping popular protests that erupted a year ago, as well as in killing and injuring thousands of demonstrators and activists who demanded reforms and an end to the influence of IRGC-backed militias in Iraq, he added.
Al-Nashou called on the Iraqi government to curb IRGC-supported militias' activities through reliance on Iraqi citizens and Iraq's security forces.