US President Donald Trump has announced the reinstatement of the United States’ blockade of Iranian shipping while unveiling plans to impose a 20% levy on all cargo transiting the Strait of Hormuz, in a dramatic move that would mark an unprecedented assertion of American control over one of the world’s most strategically important maritime chokepoints.
In a post on Truth Social on Monday, Trump declared that the Strait of Hormuz “is OPEN, and will remain OPEN, with or without Iran” following several days of intensified US military strikes against Iranian targets.
“We are reinstating THE IRANIAN BLOCKADE, so named because it is only stopping Iran’s ships or customers from entering or leaving. All other countries will have fair and open use of the Strait,” Trump wrote.
The US President also announced that Washington would henceforth assume the title of “THE GUARDIAN OF THE HORMUZ STRAIT” and argued that all cargo passing through the waterway should pay the United States a 20% fee to cover the costs of maintaining maritime security.
“The U.S.A. will be, from this point forward, known as ‘THE GUARDIAN OF THE HORMUZ STRAIT,’ but as such, and as a matter of FAIRNESS, will be reimbursed, at the rate of 20% on all cargo shipped, for any and all costs necessary to do the job of providing safety and security to this very volatile section of the World,” Trump said, adding that “the process and formation will begin immediately”.
The announcement follows four successive waves of US strikes against Iranian military assets after Tehran resumed attacks on merchant shipping, effectively ending the June Islamabad Memorandum of Understanding, which had temporarily halted hostilities and reopened the Strait of Hormuz to commercial traffic.
According to TankerTrackers, more than 80 million barrels of Iranian crude oil and refined petroleum products, valued at over US$6 billion, have departed the region during the 26 days since Washington and Tehran signed the 60-day agreement and lifted restrictions on vessels trading with Iranian ports.
“Now that the US Navy blockade is being reinstated more than a month ahead of schedule, it appears that around 30 million barrels of Iranian crude oil have yet to depart,” the tanker monitoring firm said.
Before the blockade was lifted on 18 June, US Central Command (CENTCOM) said American forces had redirected 142 commercial vessels that complied with blockade instructions and disabled nine ships that attempted to breach the restrictions.
Following the reopening of the waterway, CENTCOM said it had facilitated the safe transit of more than 800 commercial vessels through the Strait of Hormuz.
On Sunday, CENTCOM announced another round of strikes targeting Iranian air defence systems, coastal radar installations, missile and drone capabilities, and Islamic Revolutionary Guard Corps fast attack craft.
The operation also marked the first reported combat deployment of US one-way attack sea drones alongside aircraft, naval vessels and aerial drones.
The latest military action came less than 24 hours after the Cyprus-flagged container ship GFS Galaxy was struck by a projectile while transiting waters east of Oman, leaving one crew member missing and forcing the remaining crew to abandon the vessel.
Trump’s latest declaration also directly challenged Iran’s efforts to regulate access to the strategic waterway.
Earlier on Monday, Iran’s Persian Gulf Strait Authority (PGSA) announced that passage through the Strait of Hormuz was “currently unfeasible” because of recent US military operations and suspended the processing of transit permit applications until security conditions improved.
The competing declarations underscore the widening confrontation between Washington and Tehran over control and governance of the vital shipping corridor.
The Strait of Hormuz carries approximately one-fifth of global oil consumption, making it the world’s most important maritime oil transit route.
Under the United Nations Convention on the Law of the Sea (UNCLOS), ships of all nations generally enjoy the right of transit passage through international straits used for international navigation.
Although the United States is not a party to the convention, it recognises many of its navigational provisions as customary international law.
Trump’s proposed 20% transit levy would also run counter to the position adopted only days earlier by the International Maritime Organization (IMO) Council.
At its 137th session, the Council reaffirmed that ships are entitled to non-discriminatory and unimpeded transit passage through international straits and stressed that navigation through the Strait of Hormuz should remain free of tolls and transit charges.
The Council further stated that any traffic management measures introduced by coastal states must comply with international law and IMO regulations, while calling for the restoration of unhindered navigation through the internationally recognised traffic separation scheme.
Despite the far-reaching nature of Trump’s announcement, key questions remain unanswered. The White House has yet to publish an executive order, legal framework or operational guidance for shipowners, cargo interests, insurers or port authorities.
It also remains unclear how the proposed transit levy would be assessed, enforced or collected, leaving the practical implementation of both the renewed blockade and the cargo charge uncertain.