"The Iraqi people want their country back. They are calling for genuine reform and accountability and for trustworthy leaders who will put Iraq's national interests first," Secretary of State Mike Pompeo said in a statement.

The United States imposed sanctions on three Iraqis -- Qais al-Khazali, Laith al-Khazali, and Hussein Falil Aziz al-Lami -- who are part of Popular Mobilization Forces, or Hashed al-Shaabi, a Shiite militia movement close to Iran.

Some 430 people have died across Iraq as authorities cracked down on protests, which eventually led to the resignation of prime minister Adel Abdel Mahdi, a close ally of Iran.

The three militia leaders were designated under a US law that will ban them from travel to the United States and seize any assets they have in the country.

The United States also placed sanctions on an Iraqi politician, Khamis Farhan al-Khanjar al-Issawi, on bribery charges.

David Schenker, the top US diplomat for the Middle East, warned that more sanctions could come, including against government officials.