Four Iraqi militant groups affiliated with Ayatollah Ali al-Sistani, the highest Shiite authority in Iraq, said they are withdrawing from the Popular Mobilization Units (PMU) in a move that could result in a shake-up of the military organization. The four paramilitary forces, usually called the Shrine Units, are known to have an uneasy relationship with Iranian-backed militant groups in the country.

In a joint statement issued April 23, the Abbas Combat Division, Imam Ali Combat Division, Ali Akbar Brigade and Ansar al-Marja’iya Brigade said their transfer out of the PMU was authorized by a decree signed by outgoing Prime Minister Adel Abdul Mahdi, who also is the commander in chief of the armed forces.

According to the April 22 decree addressed to Faleh al-Fayadh, the Iraqi national security adviser and head of the PMU Commission, the four units will be directly under the commander in chief’s office, administratively and operationally.

One day after the Shrine Units’ joint statement, the commander in chief’s spokesman, Maj. Gen. Abdul Karim Khalaf, said that Abdul Mahdi was not consulted about the statement and that the decree is strictly about the administrative and operational arrangements of the Shrine Units. He said the prime minister does not approve of other details mentioned in the statement.