The U.S. Departments of State and Treasury sanctioned a Shanghai-based firm Tuesday, May 19, for allegedly working on behalf of the Islamic Republic of Iran's Mahan Air airline.

China's Saint Logistics is accused of providing various services to Mahan Air, including booking freight flights between China and Iran.

Secretary of State Mike Pompeo announced the sanction on the Chinese company for its business with an airline designated by the U.S. as an entity that supports terrorism.

"This designation serves as another reminder that companies still providing services for Mahan Air - in the [People’s Republic of China] or anywhere else - risk potential U.S. sanctions,” Pompeo said.

Furthermore, Pompeo said in a statement, "The People’s Republic of China is one of the rapidly dwindling number of countries that welcomes Mahan Air, which ferries weapons and terrorists around the world for the Islamic Republic of Iran. Such cooperation has consequences."

Accused of secretly transporting weapons and military forces to different regions, including Syria, Mahan Air was blacklisted and sanctioned by Washington in 2011.

Eight years later, Washington targeted Mahan Air with a new batch of sanctions for illegally transporting weapons banned by the United Nations, such as weapons of mass destruction.

The Islamic Republic has repeatedly dismissed the charges as unfounded.

However, Mahan Air's name once again came up recently for taking nine tons of gold from Venezuela to compensate Tehran's assistance in providing the fuel needed by Caracas.

Condemning the move, Pompeo tweeted on May 1, "Maduro's thugs looted nine tons of gold bars and sent it to the Iranian regime. The world's leading thieves are partnering with the world's leading state sponsor of terror. The greatest victims are the Venezuelan and Iranian people."

Steven Mnuchin, the U.S. Treasury Secretary, for his part, noted on Tuesday, “The Iranian regime is using Mahan Air to support an illegitimate and corrupt regime in Venezuela, just as it has done for the regime in Syria and terrorist proxy groups throughout the Middle East".

“We will not hesitate to target those entities that continue to maintain commercial relationships with Mahan Air,” Mnuchin added.

Mahan Air's name was also mentioned in the early weeks of the Coronavirus pandemic. Although Islamic Republic officials announced that flights between Iran and China had been suspended on January 31, 2020, Radio Farda's investigations show that Mahan flights between the two countries continued after that, and at least 55 flights were operated on this route until February 23.