US President Donald Trump also confirmed the operation, saying on Truth Social that the United States was doing “a favor to Countries all over the world” by clearing mines from the strait. Trump also claimed that all of Iran’s mine-laying ships had been destroyed.

Earlier, Axios, citing an unidentified US official, reported that two US Navy ships crossed the strait — the first such transit since the conflict began six weeks ago — and that the movement was not coordinated with Iran.

However, a regional intelligence official disputed the claim, saying two US Navy Arleigh Burke-class destroyers attempted to transit the strait but were forced to turn back after threats from Iran’s Islamic Revolutionary Guard Corps (IRGC), which also launched a UAV toward the vessels.

Iranian media also rejected the claim. The semi-official Fars news agency reported that Iranian forces monitored a US destroyer moving from Fujairah toward the Strait of Hormuz and conveyed a warning via Pakistani mediators. The vessel turned back after Tehran warned it would be targeted.

Iranian state television later said its forces issued a 30-minute ultimatum to a US destroyer approaching from Fujairah, warning it to turn back or face attack. A senior Iranian military official subsequently denied that any US ship had completed the crossing.

Ceasefire under strain

The development comes amid a fragile April 8 ceasefire brokered by Pakistan. The Strait of Hormuz, through which about 20 per cent of the world’s seaborne oil normally passes, remains effectively restricted, with Iran reportedly allowing passage only to approved vessels and charging tolls exceeding $1 million per ship, according to The Wall Street Journal.

Shipping activity remains far below normal levels. The Financial Times reported that only three supertankers crossed the strait on Saturday, compared with a pre-war daily average of about 135 vessels.

Pakistan is mediating between Washington and Tehran in Islamabad amid the two-week ceasefire, with hostilities now in their second month.

Oil flows shift as Gulf supply tightens

The disruption has begun reshaping global oil flows. Trump said on Truth Social that “massive numbers of completely empty oil tankers” were heading to the United States to load American crude.

US crude settled at $96.57 on Friday, trading at a premium to Brent crude at $95.20, reflecting rising demand for non-Gulf oil.

Historic talks remain deadlocked

Meanwhile, the Islamabad talks — the highest-level direct engagement between Washington and Tehran since 1979 — remained deadlocked.

US Vice President JD Vance led the American delegation alongside Steve Witkoff and Jared Kushner, while Iran’s 70-member team was headed by Parliament Speaker Mohammad Bagher Ghalibaf and Foreign Minister Abbas Araghchi, according to Al Jazeera.

The negotiations remain stalled over Iran’s sovereignty claims over the Strait of Hormuz, Lebanon, frozen Iranian assets, and uranium enrichment, CBS News reported. No agreement had been reached by Saturday evening.

The ceasefire is set to expire on April 22, raising concerns that tensions could escalate again if talks fail.

(With inputs from agencies)