Iran Declares Full Closure of Strait of Hormuz

Iran’s top military command announced on June 11 that the Strait of Hormuz is “completely closed to all types of vessel,” dramatically escalating the ongoing 2026 Iran War and threatening a critical chokepoint for global energy supplies. The Khatam al-Anbiya Central Headquarters declared that any vessel attempting passage “will become a target,” according to Reuters.

Context: A Crisis Months in the Making

The announcement marks the most severe phase yet of the 2026 Iran War, which began on February 28 when the United States and Israel launched coordinated airstrikes under “Operation Epic Fury,” killing Supreme Leader Ali Khamenei. The conflict has already caused what the World Bank described as “the largest oil market shock in history,” with Brent crude peaking at US$126 per barrel in March.

The Strait of Hormuz, a 34-kilometer-wide waterway connecting the Persian Gulf to the Gulf of Oman, is one of the world’s most strategically vital passages. Approximately 20 million barrels of oil — roughly 20 percent of global seaborne trade — transit the strait daily, along with a similar share of the world’s liquefied natural gas. China receives a third of its oil imports through this route, while Europe sources 12 to 14 percent of its LNG from Qatar via the strait.

What Happened: The June 10-11 Escalation

The immediate trigger for the full closure was a new wave of US strikes on June 10-11 targeting Iranian air defense systems, radars, and drone command-and-control units in southern Iran near the strait. President Donald Trump vowed to “hit them hard,” telling reporters at the White House: “We hit them hard yesterday, and we’re going to hit them hard again today.” Defense Secretary Pete Hegseth, visiting CENTCOM headquarters, echoed the sentiment: “We’ll strike ‘em hard tonight, and hopefully Iran makes a good decision.”

In response, Iran’s Islamic Revolutionary Guard Corps (IRGC) struck two vessels attempting to pass through the strait, as reported by The Straits Times. The IRGC then launched counter-attacks on 18 US military targets at airbases in Kuwait and Bahrain, triggering air raid sirens in Bahrain. Iranian media also reported explosions across the country’s south near Bandar Abbas, Qeshm Island, Minab, and Sirik.

The IRGC issued a stark warning: “We warn that no vessel should leave its anchorage in the Persian Gulf and the Sea of Oman. Approaching the Strait of Hormuz will be considered cooperation with the enemy.”

Contested Claims on the Strait’s Status

While Iran insists the waterway is fully closed, US Central Command (CENTCOM) rebutted the claim, stating that “commercial ships are continuing to transit in and out of the Strait of Hormuz tonight.” Trump separately claimed the US controls the strait and has escorted “more than 200 commercial ships” through the waterway. The conflicting accounts reflect the fog of war and the high stakes involved, as both sides seek to shape the narrative around control of this critical passage.

Global Energy Markets Under Pressure

Oil markets reacted swiftly to the escalation. West Texas Intermediate crude surged 2.6 percent to US$92.39 per barrel on June 11, adding to gains from the previous session. The World Bank had already warned that the crisis cut approximately 10 million barrels of oil per day from global supply in March, with global oil output expected to fall by 6.9 million barrels per day year-on-year in the second quarter of 2026 — its largest quarterly decline since the COVID-19 pandemic.

The economic ripple effects extend well beyond oil. Fertilizer costs have spiked 31 percent, threatening food security for an estimated 45 million people, according to research compiled from multiple sources. War-risk insurance premiums for vessels transiting the region increased four to six times in the first week of the crisis, and the International Maritime Organization reported approximately 20,000 mariners and 2,000 ships stranded in the Persian Gulf as of April.

A Fragile Ceasefire Collapses

The April 8 ceasefire that temporarily halted hostilities has effectively collapsed, even as no formal declaration of its end has been made by either side. Under that agreement, Iran had begun controlling traffic through the strait and charging tolls exceeding US$1 million per ship. A subsequent US naval blockade of Iranian ports created a “dual blockade” situation, with each side restricting the other’s maritime access.

Trump’s “Operation Project Freedom,” a US Navy mission to escort merchant ships out of the Gulf launched on May 4, was paused just two days later amid claims of “great progress” toward an agreement. But the promised deal never materialized, and tensions have steadily escalated since.

International Reactions and Diplomatic Efforts

Qatar sent a delegation to Tehran on June 10 to discuss the diplomatic process, according to the semi-official Iranian Students’ News Agency. Meanwhile, former US UN Ambassador Nikki Haley expressed deep skepticism about the prospects for a negotiated settlement, telling Bloomberg: “Iran was never going to do a deal.”

Trump himself has vacillated between threats of intensified attacks and claims that a peace deal is imminent. In a Fox News interview on June 10, he claimed he had spoken with top Iranian officials who asked him to stop the bombing, adding that bombing would stop shortly — but that the US would strike again if no agreement was signed.

What to Watch For

The full closure of the Strait of Hormuz raises several critical questions. First, can the United States effectively counter Iran’s blockade, or will the strait remain effectively closed? Second, how will global energy markets respond if the closure persists for weeks or months — the Dallas Federal Reserve has analyzed potential global output effects that could add US$20 per barrel to oil prices. Third, will China or other major powers intervene diplomatically or militarily to protect their energy supply lines?

For the approximately 20,000 mariners still stranded in the Persian Gulf, the humanitarian situation grows more precarious with each passing day. And for the global economy, already grappling with the largest oil supply disruption since the 1970s, the path forward remains uncertain. As the Al Jazeera coverage noted, this week’s hostilities mark the most intense clashes between the US and Iran in weeks, and a further escalation risks derailing any remaining diplomatic channels.

The world now watches to see whether this is the beginning of a new, more dangerous phase of the conflict — or the pressure that finally forces both sides back to the negotiating table.