The US Treasury placed two United Arab Emirates-based companies on its sanctions blacklist Wednesday for their support of Iran's already-sanctioned Mahan Air.

UAE-based Parthia Cargo and Delta Parts Supply FZC "have provided key parts and logistics services for Mahan Air," the Treasury said.

The two companies were involved in obtaining spare parts and materials for US-made jets that Mahan operates -- sanctions block Iran from freely acquiring those parts. 

Mahan, one of Iran's leading carriers, has been blacklisted under US counterterrorism regulations for its close relationship with the Islamic Revolutionary Guard Corps-Quds Force, which Washington says carries out terror activities in the Middle East.

Mahan Air especially has been used by the Revolutionary Guards to support the regimes of Syrian leader Bashar al-Assad and Venezuelan President Nicolas Maduro, according to the Treasury.

"The Iranian regime uses Mahan Air as a tool to spread its destabilizing agenda around the world, including to the corrupt regimes in Syria and Venezuela, as well as terrorist groups throughout the Middle East," said Treasury Secretary Steven Mnuchin in a statement.

"The United States will continue to take action against those supporting this airline."

The Treasury also placed sanctions on UAE-based Iranian national Amin Mahdavi, who the Treasury said either owns or controls Parthia Cargo.

The sanctions aim at blocking those targeted from accessing global financial and commercial networks by forbidding anyone from trading with them.

In a parallel move, the US Justice Department filed criminal charges in federal court in Washington against Mahdavi and Parthia for "participating in a criminal conspiracy to violate US export laws and sanctions against Iran."