Washington (CNN) -- The United States sanctioned two engineering firms Wednesday for their ties to an elite Iranian military unit that has been branded a terrorist organization by the U.S. government.
Iran Maritime Industrial Company SADRA and it subsidiary, Deep Offshore Technology PJS, are connected with Iran's Islamic Revolutionary Guard Corps-Quds Force, the U.S. Department of the Treasury said.
"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," Adam Szubin, director of the Treasury's Office of Foreign Assets Control, said in a statement.
SADRA has offices in Iran and Venezuela and is owned by Khatam al-Anbiya, which the office has designated as an engineering arm of the Quds Force, the statement said.
The Treasury Department also announced sanctions against two shipping companies based in Malta and two shipping officials connected to the Islamic Republic of Iran Shipping Lines.
The shipping lines have "played a key role in Iran's efforts to advance its missile programs and transport other military cargoes," the Treasury Department said.
The companies and individuals were sanctioned under an executive order freezing the assets of proliferators of weapons of mass destruction and their supporters, the department said
The sanctions come a day after the United States sanctioned an Iranian airline, three Iranian officials, a trading company and a shipping agent for providing support to the Quds Force.
Iran's secretive Quds Force is the elite special operations unit of Iran's Islamic Revolutionary Guard. The most militant wing of the Guard, Quds has reportedly carried out covert operations in Pakistan, Afghanistan, Lebanon and Iraq.
The United States has accused it of aiding insurgent groups behind attacks on U.S. soldiers in Iraq and Afghanistan, Jane's global security site reports.
CNN's Jamie Crawford and Ashley Fantz contributed to this report.