Two major Iraqi Shiite groups backed by Iran have demanded all U.S. forces leave Iraq, opposing plans by Baghdad and Washington to keep some there for training and advisory purposes.

The Badr Organization, a Shiite group that has a minister in Prime Minister Haider al-Abadi's government, in charge of the interior, said any remaining U.S, troops would be cause for instability.

"The two governments should coordinate to ensure a full withdrawal. U.S. presence will be cause for internal polarization and a magnet for terrorists," Badr spokesman Kareem Nuri said, as reported by Reuters. Kataib Hezbollah, a more militant, secretive and anti-American group, repeated threats to attack U.S forces.

Due to accelerated successes following the liberation of Mosul from Daesh, the U.S. will shift its focus in Iraq from enabling combat operations to sustaining public security, officials said Monday.

"Our enduring presence as invited guests in Iraq will shift to focus more on policing, border control and military capacity building," Brig. Gen. Jonathan Braga, director of operations for Combined Joint Task Force – Operation Inherent Resolve (CJTF-OIR), said in a statement.

"We will sustain the successful momentum and enhance the capacities of the Iraqi security forces in pursuing Daesh, now and in the future." Braga's remarks came after U.S. media reports claimed that the U.S. had begun reducing the number of its troops in Iraq after Baghdad's victory over Daesh. The U.S.-led international military coalition helped Iraqi forces recapture territory taken by Daesh in 2014 and 2015, providing air and artillery support in the battle to for Mosul, and trained tens of thousands of elite Iraqi soldiers. The United States has more than 5,000 troops in Iraq.