Iran warns against Hormuz crossings without authorisation

Iran's Islamic Revolutionary Guard Corps (IRGC) issued a formal warning that vessels transiting the Strait of Hormuz must use only routes officially designat...

What Happened

Iran's Islamic Revolutionary Guard Corps (IRGC) issued a formal warning that vessels transiting the Strait of Hormuz must use only routes officially designated and authorized by the Islamic Republic of Iran.
The warning came after Oman, in coordination with the International Maritime Organization (IMO), announced a new shipping corridor through the strait — a route that Iran stated had been established without prior consultation with Tehran.
Iran declared the Oman-IMO proposed route "unacceptable and posing serious safety risks," saying the only valid transit lane is the one Iran has officially designated.
The warning reintroduced tension into a fragile situation: a Memorandum of Understanding (the Islamabad MOU) signed in mid-June 2026 between Tehran and Washington had stipulated toll-free commercial transit through the strait for a 60-day period.
The IRGC further stated that vessels must maintain active contact with the IRGC Navy while transiting the waterway, effectively asserting operational control over commercial shipping.

Static Topic Bridges

Strait of Hormuz — Geography and Strategic Importance

The Strait of Hormuz is a narrow waterway connecting the Persian Gulf to the Gulf of Oman and the Arabian Sea. It lies between Iran to the north and the Oman peninsula (including the exclave of Musandam) to the south. At its narrowest navigable point, the strait is approximately 33 kilometres wide. Despite this modest width, it is the world's single most critical oil chokepoint: before the 2026 conflict, approximately 21 million barrels of oil per day — around 21% of global petroleum liquids consumption — transited through it, along with roughly 20% of the world's LNG trade. Qatar and the UAE together account for the bulk of LNG flows through this corridor.

Location: between Iran (north) and Oman's Musandam Peninsula (south)
Narrowest navigable width: approximately 30–33 km
Oil flow (pre-2026): ~21 million barrels/day (~21% of global petroleum liquids)
LNG share: ~20% of global LNG trade transits through the strait
The IMO-recognized Traffic Separation Scheme (TSS) runs two 2-nautical-mile-wide lanes — one inbound, one outbound

Connection to this news: Iran's objection to the Oman-IMO route centres on which of the strait's navigable lanes ships may use. The IRGC-controlled northern route (through Iranian territorial waters near Larak Island) is the pre-war internationally recognized TSS, while the contested new corridor runs closer to Oman's Musandam coastline.

Transit Passage Rights Under UNCLOS

The United Nations Convention on the Law of the Sea (UNCLOS), in force since 1994, governs navigation through international straits. Under Part III of UNCLOS, the right of "transit passage" applies to straits used for international navigation connecting one area of high seas (or EEZ) to another. Transit passage is a non-suspendable right — coastal states cannot deny it — but may regulate it for safety (TSS schemes) and environmental protection. Iran is a signatory to UNCLOS.

UNCLOS Part III, Articles 37–44: transit passage rights in international straits
Coastal states may designate Traffic Separation Schemes (TSS) after IMO approval
Unlike innocent passage (in territorial seas), transit passage cannot be suspended by the coastal state
IMO approves TSS under SOLAS (International Convention for the Safety of Life at Sea)

Connection to this news: Iran's insistence that ships must use only its designated corridor, and must contact the IRGC Navy, tests the limits of UNCLOS transit passage provisions. The counter-position — upheld by Oman and the IMO — is that alternative routes within the strait can be legitimately established by multilateral coordination.

The IRGC and Iran's Military-Commercial Interface

The Islamic Revolutionary Guard Corps (IRGC) is a branch of Iran's armed forces established in 1979 after the Islamic Revolution, separate from the conventional military (Artesh). The IRGC Navy controls the Persian Gulf and Strait of Hormuz operationally, including patrol craft, missile batteries on islands such as Abu Musa and the Tunbs, and submarine assets. The IRGC has been designated a Foreign Terrorist Organization by the United States since 2019.

Established: 1979, post-Islamic Revolution
IRGC Navy: controls Persian Gulf; distinct from Iran's regular Artesh Navy (which covers the Gulf of Oman and Caspian)
Operates from islands including Abu Musa, Greater Tunb, and Lesser Tunb (disputed with UAE)
Designated FTO by the United States in April 2019

Connection to this news: The IRGC Naval Force — not Iran's regular military — issued the transit warning, reflecting that the strait's operational management is an IRGC domain. Any shipping negotiation with Iran over Hormuz effectively involves the IRGC.

The Islamabad MOU (June 2026)

The Islamabad Memorandum of Understanding is a 14-point framework agreement signed in June 2026 between the United States and Iran to formalize a ceasefire and initiate a 60-day negotiating window. Its provisions include a halt to military strikes, toll-free commercial transit through the Strait of Hormuz for 60 days, lifting of the US naval blockade of Iranian ports, release of frozen Iranian assets, and a moratorium on nuclear enrichment pending a final deal. Major issues — including Iran's nuclear stockpile and weapons-grade uranium — were deferred to the 60-day negotiation phase.

Signed: June 17, 2026
Type: Memorandum of Understanding (non-binding framework; final treaty pending)
Key provision on Hormuz: toll-free commercial transit for 60 days
Unresolved: Iran's uranium enrichment levels, nuclear stockpile disposition
Negotiated with Pakistani mediation (hence "Islamabad")

Connection to this news: Iran's new warning over unauthorized transit routes creates friction with the MOU's Hormuz provision. The dispute over which lane ships may use risks undermining the resumption of commercial shipping agreed under the ceasefire framework.

Key Facts & Data

Strait of Hormuz pre-crisis oil flow: ~21 million barrels/day (~21% of global petroleum liquids)
LNG share: ~20% of global LNG trade; Qatar and UAE are the dominant LNG exporters through this route
TSS consists of two 2-nautical-mile-wide lanes designated by the IMO
Islamabad MOU signed: June 17, 2026; 60-day toll-free transit window
IRGC established: 1979; designated FTO by the US: April 2019
Over 1,550 commercial vessels were stranded near the strait as of early May 2026
UNCLOS in force: November 16, 1994; Part III governs transit passage rights in international straits