The US has imposed sanctions on Iran’s biggest shipping company and largest airline for allegedly helping Tehran develop ballistic missiles in contravention of UN sanctions.

Mike Pompeo, secretary of state, on Wednesday announced the sanctions on the Islamic Republic of Iran Shipping Lines (IRISL) and its China-based subsidiary, E-Sail Shipping, as well as Mahan Air. The move is meant to “put the world on notice those who engage in illicit transactions with these companies will risk exposure to sanctions for themselves”, Mr Pompeo said.

The sanctions on the entities, which are already subject to other US punitive actions, are being imposed under an executive order aimed at stopping the development and proliferation of weapons of mass destruction (WMD). US officials hope the measures will increase pressure on other countries to sever dealings with Iran.