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US naval blockade of Iranian ports set to begin
The United States will start enforcing a military blockade of all maritime traffic entering or leaving Iranian ports at 14:00 GMT on Monday, following failed negotiations to end the nearly two-month conflict. The move targets Iran's control of the Strait of Hormuz, a critical global shipping route.
Trump's announcement and threats
President Donald Trump declared on Sunday that the U.S. would begin "BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz." He also ordered the Navy to intercept vessels in international waters that have paid tolls to Iran, warning that "no one who pays an illegal toll will have safe passage."
Trump accused Iran of failing to reopen the strait as promised, stating, "Iran has not allowed that to happen by merely saying, 'There may be a mine out there somewhere,' that nobody knows about but them." He added that the U.S. would destroy mines allegedly laid by Iran in the waterway and vowed a severe response to any attacks: "Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!"
Scope and legal concerns
U.S. Central Command (Centcom) clarified that the blockade would apply to all vessels entering or exiting Iranian ports, including those along the Arabian Gulf and Gulf of Oman. However, ships traveling to or from non-Iranian ports would not be impeded. Centcom stated that commercial mariners would receive formal notice before enforcement begins.
While Trump suggested other nations would participate, the UK government confirmed it would not join the blockade. A spokesperson said Britain was "urgently working with France and other partners to build a coalition to protect freedom of navigation."
Legal experts raised concerns that the blockade could violate maritime law and potentially breach the current ceasefire agreement. The U.S. Navy's 2022 handbook defines a blockade as a "belligerent operation" restricting vessels of all nations from accessing enemy-controlled ports or coastal areas.
Iran's leverage and economic impact
The Strait of Hormuz, a narrow chokepoint, has been a strategic tool for Iran throughout the conflict. By selectively blocking vessels, Tehran has driven up oil prices and extracted tolls from passing ships. A U.S. blockade could cut off a key revenue stream for Iran but risks further escalating energy costs.
Trump told Fox News the goal was to prevent Iran from "making money on selling oil to people that they like and not people that they don't like," insisting the strait should be open to all or none. Analysts suggested the move was intended to pressure Iran into accepting U.S. terms for a deal.
Political reactions and shipping outlook
Republican Congressman Mike Turner framed the blockade as a tactic to force a resolution, stating, "The president is calling all of our allies and everyone to the table." However, Democratic Senator Mark Warner questioned the strategy, asking, "I don't understand how blockading the strait is going to somehow push the Iranians into opening it."
Shipping expert Lars Jensen, CEO of Vespucci Maritime, downplayed the immediate impact, noting that only a "tiny trickle" of vessels currently traverse the strait. He added that companies paying Iranian tolls already face U.S. sanctions, limiting the blockade's additional effect. Most shippers, Jensen said, are waiting to see if a peace agreement holds before resuming normal operations.
Ceasefire violations and traffic decline
A two-week ceasefire agreed on April 7 included a provision for "safe passage" through the strait. However, vessels reported receiving threats of being "targeted and destroyed" if they attempted to cross without Iranian permission. Since the truce began, only 19 ships have passed through, according to BBC Verify's analysis of MarineTraffic data-four of them tankers carrying oil, gas, or chemicals. The pre-conflict daily average was 138 vessels.
Some ships have navigated the strait without broadcasting their locations, avoiding detection.
