AT LEAST least two tankers have reversed course while attempting to transit the Strait of Hormuz via the southern channel, after Iran insisted that vessels use only Tehran‑approved routes.

The move has thrown fresh uncertainty over an IMO‑backed evacuation plan coordinated with Oman and the US, adding new complications to efforts to move stranded crews out of the region.

Singapore-flagged, 2010-built, MOL-owned crude oil tanker Azumasan (IMO: 9397157) and Togo-flagged, 2001-built, combined chemical and oil tanker Blue Star I (IMO: 9215115) were both attempting to exit the Middle East Gulf using the route approved by Oman that was part of the International Maritime Organization’s evacuation plans published earlier this week.

The IRGC navy said in a statement via official media Sepah News on Wednesday that “some authorities” announced a new route for Hormuz transit “without notifying or coordinating with” Iran, though it didn’t name any entity involved in what it called an “unacceptable and completely dangerous” plan.

“The only permitted route for passage through the Strait of Hormuz is the routes announced by the Islamic Republic of Iran,” the IRGC said, adding that vessel movements outside those routes were “highly dangerous and prohibited”.

It said that coordination with the IRGC Navy via VHF Channel 16 was “mandatory” and that “action will be taken against violating vessels”.

The warning from IRGC appears to contradict with a plan announced by IMO on Tuesday to evacuate more than 11,000 seafarers stranded in the Middle East Gulf after the agency said it had secured “necessary safety guarantees”. The conflicting instructions create new uncertainty for ships weighing how to leave the MEG safely.

Blue Star I was just rounding the Omani peninsula when it decided to perform a U-turn at 0718 hrs on June 25. It returned eastwards and is now waiting off Khasab, Oman.

Azumasan did not get as far. Instead, it U-turned before Khasab at 0751 hrs and is again waiting in the Middle East Gulf.

IMO secretary-general Arsenio Dominguez said in a statement yesterday that its evacuation plan would be carried out in cooperation with Iran, Oman, other coastal states, the US and the maritime industry.

To support these operations, the IMO has “thoroughly verified the conditions for safe navigation”, Dominguez said. “We remain fully committed to ensuring the safety of seafarers and the continuity of global trade.”

An IMO spokesperson told Lloyd’s List on Thursday that its evacuation framework continues to be implemented as planned.

“Vessels are encouraged to follow the operational FAQs shared on the IMO website,” the spokesperson said.

Operational guidance issued by the IMO says vessels should not move until contacted through a coordinated mechanism involving UKMTO and the MICA Centre in order to mitigate mine-related risks.

Once contacted directly, ships may proceed to a designated waiting area and then choose either a northern route through Iranian waters or a southern route through Oman and US-coordinated waters, after conducting their own risk assessment.

The existing traffic separation scheme “should not be used due to the reported presence of mines”, IMO said, adding that it doesn’t directly coordinate routing and maritime safety.

In a separate statement, Oman confirmed a southern route through the Strait of Hormuz would be available for vessels seeking to transit eastbound out of the Middle East Gulf. For the Oman-authorised eastbound transit route, vessels are told to contact radio station “A4N” on VHF Channel 16 before reaching the first waypoint.

Following the announcement, Danish shipping group Norden confirmed that the first of its seven chartered vessels in the Gulf has now been able to leave the area safely. The vessel, a handy-size dry cargo ship carrying fertiliser to Australia, is the first of the company’s chartered fleet to clear the region since the crisis began.

“We view this as a positive development after several months of significant disruption and uncertainty in and around the Strait of Hormuz,” chief executive Jan Rindbo said.

“The recent developments in the region are positive for the world economy, global trade, NORDEN and our valued customers — and not least the seafarers onboard the vessels.”

Norden said it continues to monitor the situation closely.

According to Lloyd’s List Intelligence tracking data, traceable traffic through Hormuz jumped 270% to 119 transits last week after a Memorandum of Understanding between Washington and Tehran partially reopened the waterway amid volatile political negotiations.

The surge in transits, however, masks the confused, two-tier system now operating in the strait, which remains split between the Iran-controlled northern route and a US-protected southern “highway”, with the pre-war routes, rendered unusable because of the risk of mines, separating them.

The figure, though sharply higher than that of recent weeks, is still far below the 700 recorded during the same period last year.

The immediate risk of an outright closure of the Strait of Hormuz, or military confrontation there, has “substantially” decreased, but recent diplomatic developments should not be read as a return to unrestricted commercial navigation, security consultancy Marisks said Wednesday in a client update.

The IRGC has reportedly stopped issuing new transit permits for the Tehran-controlled northern corridor, with only vessels that already hold permission, or those directly selected by Iranian authorities, currently being allowed to pass, according to Marisks.

The southern route through Omani territorial waters, meanwhile, is being widely used by vessels with no Iranian affiliation, Marisks said, adding that those ships are transiting without incident under US coordination so far.