"The Blockade will begin shortly. Other Countries will be involved with this Blockade," Trump wrote on Truth Social.
The US Navy will be blockading "any and all Ships trying to enter, or leave, the Strait of Hormuz," until all are allowed to go in and out, he wrote.
"I have also instructed our Navy to seek and interdict every vessel in International Waters that has paid a toll to Iran. No one who pays an illegal toll will have safe passage on the high seas," Trump also said.
The US leader added that he would not allow any country, especially his own, to be "extorted" by Iran.