The United States on Wednesday expanded its sanctions against Iran to cover four entities and two individuals associated with the country's elite Islamic Revolutionary Guard Corps (IRGC) and national shipping company.

The Department of Treasury said that Iran Maritime Industrial Company SADRA (SADRA), with offices in Iran and Venezuela, is targeted for being owned by Khatam al-Anbiya, an engineering company used by the IRGC to fund its operations.

Deep Offshore Technology PJS was blacklisted as a subsidiary wholly-owned by SADRA.

The Treasury said that any foreign financial institution knowingly doing business with the two firms faces potential loss of its correspondent account access to the United States.

Modality Limited and Malship Shipping Agency Ltd., two companies based in Malta, were put under sanctions as they are affiliates of the Islamic Republic of Iran Shipping Lines (IRISL).

Seyed Alaeddin Sadat Rasool and Ali Ezati, two IRISL officials, were listed for sanctions as well.

The IRGC is a primary target of sanctions by the U.S. and other countries, as Washington points to the central role it plays in Iran's missile and nuclear programs, as well as its support for terrorism and its involvement in "serious" human rights abuses in the Islamic republic.

"The IRGC has continued to expand its control over the Iranian economy, in particular in the defense production, construction, and oil and gas industries," the Treasury said in a statement.

The IRISL is accused of playing a key role in Iran's efforts to advance its missile programs and transport other military cargoes.

"By designating the individuals and entities today, Treasury is sending a clear signal to the international community that Iran's attempts to evade international sanctions will not go unnoticed," said Adam Szubin, director of the Treasury's Office of Foreign Assets Control.

"We will continue to target the Iranian regime and specifically the IRGC as it attempts to continue its nefarious infiltration of the Iranian economy," he added.