Hours after US President Donald Trump rejected a diplomatic solution put forward by Iran to reopen the Strait of Hormuz, explosions were heard in the waterway, according to Iranian media.

Reports of blasts near southern Iran’s Qeshm Island in the Strait of Hormuz suggested that multiple antiship missiles and drones were fired at vessels transiting the waterway against Tehran’s wishes. While Iranian authorities did not confirm any attacks in the Strait of Hormuz that day, shipping continues to be attacked in the waters, including an Indian cargo ship last week, which killed a sailor The Islamic Revolutionary Guard Corps (IRGC) maintains that the strait is closed to any ship that does not coordinate with Iranian authorities. On Sunday afternoon, it released video of what it said was a second US underwater drone seized this month.

While Iranian authorities did not confirm any attacks in the Strait of Hormuz that day, shipping continues to be attacked in the waters, including an Indian cargo ship last week, which killed a sailor The Islamic Revolutionary Guard Corps (IRGC) maintains that the strait is closed to any ship that does not coordinate with Iranian authorities. On Sunday afternoon, it released video of what it said was a second US underwater drone seized this month.

Tehran has issued instructions to shipping companies transiting the Strait of Hormuz to use a temporary route approved by Iranian authorities and pay relevant fees. But it has also said the strait will not fully reopen until the US blockade on Iranian ports ends.

Iran’s Persian Gulf Strait Authority announced on Saturday that it would blacklist any shipping charterer company which orders crews to use routes it considers to be unauthorised.

It also published what it described as an apology from an unnamed shipowner blaming commercial pressure from its charterer for trying to pass through the strait. Washington still insists that its warships are successfully guiding oil tankers out of the strait via a different route. US Energy Secretary Chris Wright told Fox News on Sunday that the “running average” of crude oil in transit was nearly 13 million barrels per day.

Washington still insists that its warships are successfully guiding oil tankers out of the strait via a different route. US Energy Secretary Chris Wright told Fox News on Sunday that the “running average” of crude oil in transit was nearly 13 million barrels per day.

A September 19 operational update by US Central Command claimed that its forces had helped move more than one billion barrels of crude out of the Gulf over roughly two months.

The US military also says its forces have redirected 122 commercial vessels to enforce the naval blockade of Iran’s ports halting all Iranian crude exports. Tehran has claimed that the US is providing false information regarding Strait of Hormuz traffic to project control over the key waterway. Shipping has been severely disrupted since the US and Israel started their war on Iran on February 28.

Andreas Krieg, associate professor at King’s College London, said Iran’s strategy of launching maritime attacks has spread the economic costs of the conflict beyond its borders. While Iran has suffered economically from war damages, the US naval blockade and sanctions, it would be a mistake “to assume that reaching that threshold produces submission”.

“The next Iranian move is therefore likely to be an attempt to increase the pain experienced by the Gulf rather than simply absorb further American pressure,” Krieg said.

“That could mean more aggressive vessel interdictions in Hormuz, attacks on energy infrastructure, greater Houthi pressure around Bab al-Mandeb and pressure from Iranian-aligned groups against alternative Saudi export routes. We are already seeing how pressure on Hormuz, the Red Sea and Saudi infrastructure can interact.” The flight deck of the USS George Washington aircraft carrier in the Arabian Sea, September 11, 2026 [Ed Ou/Reuters] More escalation on the way At the United Nations General Assembly in New York, Iran projected a message of defiance while also proposing to reopen the Strait of Hormuz within a week if its seven conditions were met.

“That could mean more aggressive vessel interdictions in Hormuz, attacks on energy infrastructure, greater Houthi pressure around Bab al-Mandeb and pressure from Iranian-aligned groups against alternative Saudi export routes. We are already seeing how pressure on Hormuz, the Red Sea and Saudi infrastructure can interact.” The flight deck of the USS George Washington aircraft carrier in the Arabian Sea, September 11, 2026 [Ed Ou/Reuters] More escalation on the way At the United Nations General Assembly in New York, Iran projected a message of defiance while also proposing to reopen the Strait of Hormuz within a week if its seven conditions were met.

They included lifting the blockade on Iran, the release of frozen Iranian funds and an end to attacks on all fronts, including Israel’s assault on Lebanon. The demands mostly amounted to a return to the June memorandum of understanding between the US and Israel Tehran has added that reopening the strait must be undertaken through a bilateral arrangement already finalised with Oman, the only other country with territorial waters in Hormuz.

US President Donald Trump told reporters he rejected the offer, but Iran’s Foreign Minister Abbas Araghchi said on Sunday they were adamant about the conditions and would await an official response through mediators, such as Pakistan, Qatar and Oman.

Abolfazl Shekarchi, chief spokesman of the Iranian armed forces, warned that if the US further intervenes in the Strait of Hormuz, “it will get slapped”. “The Americans have no way out other than withdrawing from the West Asia region. The sooner they leave, the fewer losses they will incur and the region will certainly become safe after that,” he said.

Iranian army spokesman Mohammad Akraminia said conditions were deteriorating so badly for the US that it might launch another “military aggression” on Iran.

Krieg said that as the US moves to isolate Iran via sanctions, Tehran, unable to respond with mutual financial measures against Washington, will be forced to rely on continued coercion in the Strait of Hormuz. “The most likely level remains controlled attrition rather than an immediate return to the massive air campaign of the opening months,” Krieg said. “Over the coming weeks, I would expect further attacks or attempted attacks on tankers, US-enabled shipping and regional infrastructure, followed by limited US strikes against IRGC maritime assets, coastal missile positions, drones or vessels involved in those operations. That tit-for-tat cycle has already re-emerged around Hormuz.”