The US Treasury on Tuesday blacklisted Harakat al-Nujaba, an Iran-backed militia that is part of the Hashd al-Shaabi.
The group is made up of Iraqis, but is known to have close ties to Iran and Lebanese Hezbollah and has been active in both Iraq and Syria.
Harakat al-Nujaba rejects American military presence in Iraq and its members have said US forces stationed in the country should be targeted.
The militia was formed in 2013 by Akram al-Kaabi who had previously been a leader within another Iran-backed Shiite militia, the Asaib Ahl al-Haq. He was designated a terrorist by the US Treasury in 2008.
Harakat al-Nujaba claims to have 10,000 members, according to the Foundation for Defense of Democracies, and is believed to be playing a role in expanding Iranian influence across Iraq and Syria as part of the so-called “Shiite crescent.”