Shippingtelegraph: US tells American ships to ignore Iranian directions

The US has issued a new advisory to U.S.-flagged vessels transiting the Persian Gulf, Strait of Hormuz and Gulf of Oman to maintain a minimum standoff of 30 nautical miles from U.S. military vessels to reduce the risk of being mistaken as a threat and to answer all VHF calls from coalition navies.

The U.S. Department of Transportation’s Maritime Administration warned that U.S. and other coalition naval forces may conduct maritime awareness calls, queries, and approaches to ensure the safety of vessels transiting these waters.

“U.S.-flagged commercial vessels should closely coordinate voyage planning with U.S. Naval Forces Central Command (NAVCENT) Naval Cooperation and Guidance for Shipping (NCAGS) and consider their recommendations and guidance whenever possible. NAVCENT NCAGS stands a 24/7 watch and has the latest information on the current maritime security threats and the operational environment in this region,” the U.S. Maritime Administration (MARAD) said in a maritime advisory.

Under the guidance, MARAD warns that Iranian forces may attempt to contact vessels via VHF radio or email and instruct them to divert from their planned course or submit voyage information.

U.S.-flagged ships are instructed to ignore the email or call and continue their passage if safe to do so.

U.S. officials advise vessels that encounter these tactics not to follow Iranian directions, as doing so may enhance the ability of Iranian forces to accurately target vessels.

U.S.-flagged commercial vessels are also advised to update NAVCENT NCAGS when any such communications or anomalous behavior occur.

Significant GNSS interference, spoofing, and jamming continue across these areas. Given the degraded positional integrity environment, mariners should increase reliance on traditional navigation methods including radar ranges, visual bearings, and cross-checking ECDIS inputs with secondary navigation systems.

It is recommended that U.S.-flagged commercial vessels transiting these waters remain as far as possible from Iran without compromising navigational safety. When transiting eastbound in the Strait of Hormuz, it is recommended that vessels transit close to Oman.

Furthermore, U.S.-flagged commercial vessels operating in these waters are advised to conduct a pre-voyage risk assessment, incorporate appropriate protective measures into vessel security plans, exercise caution, and monitor VHF Channel 16.

In the event of any attack, incident, or suspicious activity, immediately activate the Ship Security Alert System, contact the U.S. Fifth Fleet Battle Watch, and contact the United Kingdom Maritime Trade Office (UKMTO).

The advisory will remain in effect from March 13 until September 9, 2026. The advisory supersedes and cancels U.S. Maritime Advisory 2026-001.