The British maritime security monitor UKMTO said one container ship reported it was fired upon by an Iranian Revolutionary Guards boat near the entrance to the strait on Wednesday, causing damage to the bridge but no casualties.

Iranian authorities said they consider the U.S. blockade of the country’s ports as an act of war and a violation of any ceasefire agreement.

One of the cargo ships was 'heavily damaged' by Iranian forces, a British maritime agency reported on Wednesday.