The Obama administration imposed new sanctions against Iran’s largest air carrier, accusing it of aiding government organizations that support international terrorism and nuclear proliferation.

According to The Washington Post, the new measures announced by the Treasury Department allege links between Iran Air, the country’s national airline, and illegal weapons shipments to terrorist groups in Syria, and also to the transport of high-tech parts for Iran’s advanced missiles and nuclear programs.

The sanctions restrict U.S. firms from conducting business with the airline in the United States or overseas. Also targeted for sanctions was Tidewater Middle East Co., a major port operator in Iran.

U.S. officials said the measures were indirectly aimed at Iran’s powerful Islamic Revolutionary Guard Corps, whose leaders are alleged to dominate the country’s illicit trade in weapons parts and technology. A statement attributed to Secretary of State Hillary Rodham Clinton and Treasury Secretary Timothy Geithner said the United States would seek to “sharpen the choice for Iran’s leaders to abandon their dangerous course.”