Faleh al-Fayyadh, who heads the force mostly integrated into the state, told reporters in Baghdad he wanted "the fall of corruption, not the fall of the regime."

The rallies began on Tuesday with calls to reduce youth unemployment and corruption but have spiralled to demand a total overhaul of the Iraqi political system.

The Iraqi government has announced a series of reforms to create jobs, boost social welfare and oust corrupt officials but have also accused "saboteurs" of infiltrating the protests.

"We know who stands behind these protests. The plan to bring down the regime has failed," Fayyadh said.

His words echoed a statement earlier Monday by Iran's supreme leader Ayatollah Ali Khamenei who accused "enemies" of trying to drive a wedge between Tehran and Baghdad.

State news agency IRNA said he was reacting to recent violence in Iraq.