LONDON, April 13 (Reuters) - The U.S. military will enforce a blockade nL6N40V09S in the Gulf of Oman and Arabian Sea east of the Strait of Hormuz that will apply to all vessel traffic regardless of flag, the U.S. Central Command said in a note to seafarers seen by Reuters on Monday.
The note said the blockade would come into effect at 1400 GMT on Monday.
"Any vessel entering or departing the blockaded area without authorization is subject to interception, diversion, and capture," the note said.
"The blockade will not impede neutral transit passage through the Strait of Hormuz to or from non-Iranian destinations."
U.S. President Donald Trump announced the blockade following the breakdown of talks https://www.reuters.com/world/asia-pacific/us-iran-talks-pause-now-disagreements-remain-2026-04-11/ to end the six-week-long war between the U.S. and Iran that took place over the weekend, sending oil prices back above $100 a barrel. The blockade adds to uncertainty https://www.reuters.com/world/asia-pacific/us-blockade-iran-will-be-major-military-endeavor-experts-say-2026-04-13/ around how ships will transit the crucial waterway, used to move one-fifth of the world's oil and gas supplies.
The blockade "encompasses the entirety of the Iranian coastline to include but not limited to ports and oil terminals", the note said, adding that humanitarian shipments including food, medical supplies, and other essential goods would be permitted, subject to inspection.
Shipping industry sources on Monday said that the uncertainty over the blockade's enforcement was another complication for vessels stuck in the Gulf.
"The US announcing plans to blockade the Strait of Hormuz brings more uncertainty to the situation. Transits through the strait have picked up in recent days but remain well below pre-crisis levels," ship broker Clarksons said in a note on Monday.
FEW VESSELS TRANSIT GULF BEFORE BLOCKADE
Tehran has threatened to retaliate against ports https://www.reuters.com/world/middle-east/us-blockade-iran-after-talks-fail-yield-a-deal-2026-04-13/ of its Gulf neighbours, after weekend talks failed to reach a deal to end the war, leaving a ceasefire in jeopardy.
Two oil tankers linked to Iran exited the Gulf nL1N40W09N on Monday via the strait ahead of the planned U.S. blockade, shipping data from Kpler and LSEG showed.
The tanker Aurora is laden with Iranian oil products, while the New Future tanker is carrying diesel loaded from the Hamriyah port in the United Arab Emirates, Kpler data showed.
A separate oil products tanker that loaded in a United Arab Emirates port sailed through on Monday, along with three dry bulk ships that left from Iranian ports, according to Kpler. Ships also sailed into the Gulf on Monday via the strait, including two Pakistan oil products tankers and two dry bulk ships.
(Reporting by Jonathan Saul and Arathy Somasekhar, editing by Jason Neely, Keith Weir and David Gaffen)
