Donald Trump hopes of extricating himself from his war on Iran were dealt another blow on Saturday after Tehran closed the strait of Hormuz again after the president said the US would not end its blockade of Iranian ports.

Earlier, Trump said in a social media post: “The naval blockade will remain in full force and effect as it pertains to Iran, only, until such time as our transaction with Iran is 100% complete,” adding that “this process should go very quickly”.

On Saturday, Tehran reversed course on opening the waterway vital to oil shipments, and a UK maritime agency reported that Islamic Revolutionary Guard Corps (IRGC) ships had fired at a tanker as it attempted to pass through the strait on Saturday. Reuters reported separately that an Indian-flagged vessel carrying crude oil had also been attacked while in the waterway.