German finance regulator BaFin said Friday it had banned a Hamburg-based branch of Bank Melli Iran from issuing loans citing infringement of transparency rules.

"BaFin had identified contraventions of the requirements for proper business organisation within the meaning of section 25a (1) of the German Banking Act caused by infringement of the four-eyes principle," BaFin said in a statement.

BaFin said its order became final on Oct. 7. It is not clear if the infringements had anything to do with US banking sanctions on Iran.

Iranian banks have opaque practices and an international watchdog, the Financial Action Task Force (FATF) has put Iran on its blacklist along with North Korea for lack of financial transparency. This has put limits on Iran's banking relations with the world.

US sanctions have also impacted Iran's banking system. Former US President Donald Trump withdrew from the 2015 nuclear accord between Iran and world powers, including the European Union, and reimposed a wide array of sanctions on the Islamic Republic, which made it almost impossible for Iranian banks to do business in the West.

The Biden administration wants to revive the accord.