What is a naval blockade and how would it work in Strait of Hormuz?
What is a naval blockade and how would it work in Strait of Hormuz?
The U.S. military announced plans to enforce a maritime blockade targeting all vessels accessing Iranian ports, effective Monday. This move aims to restrict traffic in the Strait of Hormuz, a vital waterway where Iran has previously closed movement to exert pressure. The blockade follows stalled negotiations between the U.S. and Iran to end hostilities, which began on 28 February.
President Donald Trump claimed that talks in Pakistan faltered because Iran was “unwilling to give up its nuclear ambitions.” In response, Iran’s foreign ministry accused the U.S. of “excessive demands and unlawful requests.” On Sunday, Trump posted to Truth Social, stating the U.S. would “BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz.” He directed the U.S. Navy to intercept every vessel in international waters that had paid Iran a toll, vowing that “No one who pays an illegal toll will have safe passage on the high seas.”
Additionally, Trump said U.S. forces would destroy mines Iran had laid in the strait. “Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!” he declared. He argued that Iran had prevented free passage by merely suggesting “There may be a mine out there somewhere,” despite not confirming its presence. Trump also noted that Iran had promised to open the strait but “knowingly failed to do so,” urging them to “begin the process of getting this INTERNATIONAL WATERWAY OPEN AND FAST.”
The U.S. Navy Commander’s handbook from 2022 defines a blockade as a “belligerent operation to prevent vessels and/or aircraft of all States, enemy and neutral, from entering or exiting specified ports, airfields, or coastal areas belonging to, occupied by, or under the control of an enemy State.” Initially, Trump stated the blockade would take effect “effective immediately,” later clarifying it would “be effective pretty soon” and described it as an “all or none” policy.
On Monday, the U.S. Central Command (Centcom) announced the blockade would start at 10:00 EDT (15:00 BST). It emphasized the action would target vessels of all nations entering or departing Iranian ports, including those in the Arabian Gulf and Gulf of Oman, while allowing free transit for ships heading to non-Iranian destinations. A formal notice would also be shared with commercial mariners before enforcement began.
The BBC reports the UK will not join the blockade, though Trump mentioned NATO allies would assist. He told Fox News that the alliance has offered to “clean out” the strait, ensuring its reusability “in not too long a distance.” The UK, a NATO member, is already deploying mine-hunting systems in the region. A UK government spokesperson reiterated support for “freedom of navigation,” stating the strait “must not be subject to tolling” and that efforts with France and others are ongoing to protect global trade.
Legal experts in the U.S. raised concerns about the blockade’s compliance with maritime law. One questioned whether the military enforcement would breach the current ceasefire agreement. The strait’s strategic location has long allowed Iran to leverage its control, selectively blocking vessels and inflating oil prices. By closing the waterway, Trump aims to cut Iran’s revenue but risks sending a signal of escalation.
Key Details
Blockade timing: Monday at 10:00 EDT. Target: Iranian ports and coastal areas. Non-Iranian ships allowed through. Legal uncertainty: Potential violations of maritime law. NATO’s role: Assisting in clearing mines. UK’s stance: Supporting open passage, not participating directly.
“I have also instructed our Navy to seek and interdict every vessel in International Waters that has paid a toll to Iran.”
“Iran promised to open the Strait of Hormuz, and they knowingly failed to do so.”
“Any Iranian who fires at us, or at peaceful vessels, will be BLOWN TO HELL!”
“The blockade will be enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas.”