Seeking to increase sanctions pressure on Iran, the Treasury said it has blacklisted a major Iranian port operator and the country's national airline, Iran Air.

The actions target two key segments of Iran's transport infrastructure that the Treasury said were being used to aid Tehran's efforts to develop weapons of mass destruction.

The actions prohibit US entities from any transactions with Tidewater Middle East Company, which operates seven port facilities in Iran, and Iran Air, which serves 35 international and 25 domestic destinations with a fleet of about 40 aircraft.

The Treasury's designation of the firms as weapons proliferators also seeks to freeze any assets they may have under US jurisdiction.-Reuters