U.S. Begins Naval Blockade of Iran as Allies Refuse to Join
The Strait of Hormuz — through which roughly one-fifth of the world's oil flows — is now a flashpoint of direct U.S.-Iranian confrontation. With diplomatic efforts collapsed and fragile ceasefire agreements set to expire in nine days, the blockade is the sharpest escalation yet.
By Tongzhi AI | April 13, 2026
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The United States launched a naval blockade of Iran on Monday, attempting to cut off all maritime access to Iranian ports — a dramatic escalation in a nearly six-week-old war that has sent oil prices surging past $100 a barrel and left the global economy on edge.
U.S. Central Command (CENTCOM) announced that American warships would intercept any vessels — regardless of nationality — sailing to or from Iranian ports or coastal waters. The blockade took effect at 10:00 a.m. Eastern Time (2:00 p.m. GMT) on Monday. The Strait of Hormuz, a narrow passage between Oman and Iran through which approximately 20 percent of the world's oil supply passes, is the critical chokepoint at the centre of the standoff.
The move came less than 48 hours after direct negotiations between the United States and Iran collapsed in Islamabad. Special Presidential Envoy Steve Witkoff led the American delegation; Iran's team was headed by Parliament Speaker Mohammad Bagher Ghalibaf. Both sides described the talks as "tough" but ultimately fruitless, with the two governments unable to bridge fundamental differences over Iran's nuclear programme — which has survived two decades of international diplomacy and more than five weeks of American and Israeli strikes.
"We think that numerous countries are going to be helping us with this also," President Trump told Fox News on Sunday. As of Monday morning, no country had publicly committed to joining the operation.
An Alliance of None
Britain declined immediately. Prime Minister Keir Starmer spoke with French President Emmanuel Macron, and the two agreed their countries would instead work to restore shipping through the Strait of Hormuz — not enforce the blockade. Spain's Defence Minister Margarita Robles was blunter. "Trump's proposed blockade makes no sense," she said in a television interview. "Since this war started, nothing makes sense. This is another episode in the downward spiral the world has been dragged into." Australia said it had not been asked to assist and urged de-escalation. China — Iran's largest oil customer and a major shipping power with vital interests in the Strait of Hormuz — did not issue a public response. The silence from Beijing, which has historically hedged between its strategic partnership with Tehran and its dependence on Gulf energy imports, underscored how few major powers had rallied to Washington's position. Israel, which has conducted strikes alongside the United States since late February, also did not immediately indicate whether it would participate in or support the naval blockade. Germany, already contending with severe economic fallout from the conflict — its economy contracted in 2023 and 2024 following Russia's invasion of Ukraine and grew just 0.2 percent last year — announced an emergency package including a temporary fuel tax cut and a €1,000 relief bonus for workers, as Chancellor Friedrich Merz warned: "We will feel the consequences of this war for a long time to come."
A German foreign policy spokesperson, Jurgen Hardt of the CDU/CSU parliamentary bloc, offered a dissenting read: he called Trump's blockade remarks a "strategic negotiating maneuver" rather than a settled policy, noting that disrupting a global trade route would raise prices in the United States itself and weaken Trump's domestic political position. "Not every word from the U.S. president should be regarded as a final decision," Hardt told the Rheinische Post.
Iran Responds
Iranian forces have already clashed with U.S. warships in the Strait. Press TV, Iran's English-language state broadcaster, reported that at least two American Navy destroyers attempted to transit the Strait of Hormuz but were intercepted by Iranian naval units and forced to turn back. The Islamic Revolutionary Guard Corps (IRGC) issued a statement treating the approach of American military vessels to the Strait as a violation of the existing ceasefire agreements — raising the question of whether those agreements have now effectively collapsed. The IRGC reaffirmed that the Strait remains open for civilian vessels under special regulations.
"No port in the Persian Gulf will remain safe if Iranian ports are threatened," said Ebrahim Zolfaghari, spokesman for the Khatam al-Anbiya Central Headquarters, calling the U.S. blockade "illegal" and "piracy." The Iranian Embassy in Thailand called the blockade decision "ridiculous."
Tehran also received a diplomatic overture. The Kremlin repeated its offer to take custody of Iran's highly enriched uranium as part of any peace agreement — a proposal first made by President Putin in conversations with Washington and regional states. Kremlin spokesman Dmitry Peskov said the offer "still stands, but has not been acted upon," and criticized the blockade as likely to continue harming international markets.
Nine Days to a Ceasefire Deadline
The blockade is set against a ticking clock. Fragile ceasefire agreements — put in place after the first week of U.S.-Israeli strikes on Iran in late February — are currently set to expire on April 21. Efforts to negotiate a permanent end to the fighting before that date are ongoing, though they have so far failed.
Mediators from Egypt, Pakistan and Turkey are pressing for a new round of U.S.-Iran talks before the deadline, Axios reported on Monday, citing regional officials. A senior U.S. official described the Islamabad talks as "tough" but "a friendly and productive exchange of proposals," and a regional official said: "The door is not closed yet. Both sides are bargaining." Turkey has separately called for a broader Middle East security pact in the wake of the conflict.
Pope Leo, who has publicly broken with the Trump administration over its conduct of the war, said on Monday he would "continue to speak out" against armed conflict. "I am not afraid," he said in remarks widely interpreted as a direct response to criticism from the White House.
The Stakes
The Strait of Hormuz is among the world's most strategically vital waterways. An effective blockade — particularly one enforced without international partners — risks triggering a broader regional conflict, disrupting global energy markets, and complicating the diplomatic path to any ceasefire. The absence of allied support for the U.S. operation leaves Washington acting alone, or nearly so, in enforcing what amounts to a de facto act of war against a country of 88 million people.
Oil markets reacted sharply. Brent crude traded above $100 a barrel on Monday, reflecting fears that the blockade could restrict Gulf supplies at a moment when global energy infrastructure is already under strain from the conflict's broader disruption.
The next nine days will determine whether mediators can broker a last-minute deal — or whether the collapse of diplomacy gives way to a significant widening of a war that has already killed thousands and destabilised the global economy.
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Sources: TASS, The New York Times, The Washington Post, Politico Europe, The Moscow Times, Deutsche Welle, Reuters
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