One ship and two shipping companies have been blacklisted by the US as outgoing president Donald Trump slaps ever-more Iranian companies with sanctions.

The 6,300-dwt cargoship Bosco Gilan (built 1999) was sanctioned by the US Treasury's Office of Foreign Assets Control on Wednesday, amid a swathe of blacklistings against Iranian firms tied to the quasi-public entity known as Bonyad Mostazafan.