The U.S. Treasury Department said on Tuesday it was expanding sanctions on Iran to include 10 "shipping and front companies and one individual based in Malta" affiliated with the Islamic Republic of Iran Shipping Lines (IRISL).

"As IRISL and its subsidiaries continue their deceptive efforts to escape the grasp of U.S. and international sanctions, we will continue to take action - as we are today - to expose the front companies, agents and managers working with IRISL and work to stop this illicit business," David Cohen, U.S. Under Secretary for Terrorism and Financial Intelligence, said in a statement.

The move is part of a continuing U.S. effort to stop Iran's nuclear weapons program by freezing the assets of individuals and companies that support the program and denying them access to the U.S. financial system and commercial market.

IRISL is already facing international sanctions for its involvement in Iran's efforts to advance its missile programs and transport military cargoes, the Treasury Department said.

Jamshid Khalili, an Iranian national who is chief executive and managing director of the shipping company Irano Hind, was also designated for sanctions, the department said.

Irano Hind is an IRISL-Shipping Corporation of India joint venture that is already subject to both U.S. and United Nations Security Council sanctions, the Treasury Department said.

The newly designated companies are: BIIS Maritime Limited, ISIM Amin Limited, ISIM Atr Limited, ISIM Olive Limited, ISIM Sat Limited, ISIM Sea Chariot Limited, ISIM Sea Crescent Limited, ISIM Sinin Limited, ISIM Taj Mahal Limited and ISIM Tour Limited.