The US is giving plenty of warning ahead of its latest round of sanctions against Iran's shipping industry.

In 180 days — 8 June, 2020 — the Islamic Republic of Iran Shipping Lines will be added to the US Treasury's blacklist, after the company allegedly aided Iran in its development of weapons of mass destruction.

US Secretary of State Mike Pompeo said the company had sanctions lifted under the 2015 nuclear deal scuttled by President Donald Trump last year.