Iran’s Islamic Revolutionary Guard Corps (IRGC) has warned shipowners against using any new transit routes through the Strait of Hormuz without Tehran’s approval, threatening action against vessels that fail to comply with Iranian instructions.

The IRGC declared that any new transit route through the Strait of Hormuz established without coordination with Tehran is “unacceptable and dangerous.”

The warning signals Iran’s determination to maintain control over navigation through the strategic waterway despite a memorandum of understanding signed with the United States last week aimed at reopening the vital energy corridor after months of conflict.

According to Iranian media reports, the IRGC Navy said only shipping lanes designated by Iran are authorised for passage and that vessels must coordinate with Iranian forces through established communication channels.

“Navigation outside these routes is highly dangerous and prohibited,” the IRGC Navy said, urging all vessels to avoid travelling beyond designated corridors.

The statement came days after a leading maritime information group recommended alternative shipping routes through the strait, advising shipowners to use a southern corridor along Omani territorial waters with transponder signals activated.

The advisory said the southern route had been cleared of mines and was considered the preferred option for transit.

Shipping activity through the Strait of Hormuz has shown signs of recovery, though traffic remains below pre-conflict levels.

Data from vessel-tracking firm MarineTraffic showed that transits rose to 93 over the weekend, nearly triple the volume recorded during the previous comparable period.

Before the conflict, more than 100 vessels passed through the strait daily.

MarineTraffic also reported 31 verified crossings by commercial and energy-carrying vessels on Tuesday, noting that operators continue to adopt a cautious approach by using a combination of Iranian, Omani and International Maritime Organisation-approved routes.

The dispute over navigation comes amid growing international scrutiny of Iran’s role in the waterway.

In May, the United States imposed sanctions on Iran’s Persian Gulf Strait Authority, accusing it of attempting to “extort global maritime trade.”

US Treasury Secretary Scott Bessent warned that Washington would oppose any system of tolls or restrictions on shipping through the strait.

Analysts say continued Iranian influence over the Strait of Hormuz could have lasting implications for global energy markets, with tanker traffic unlikely to return fully to pre-war levels if Tehran retains operational control of the chokepoint.

Helima Croft, head of global commodity strategy at RBC Capital Markets, said any post-conflict arrangement that leaves Iran exercising significant control over the strait would likely result in lower shipping volumes through one of the world’s most important oil transit routes.