A U.S. defense official, speaking on the condition of anonymity, said in the past seven days more than 100 vessels had directly coordinated with the U.S. military to pass through the strait and over 300 had passed through the region more generally, evidence that the U.S.-led efforts were working, even if volumes remain below pre-war levels.
Iran threatened on Wednesday to shut off more regional energy exports, after the U.S. re-imposed a naval blockade of Iranian ports and both sides launched more strikes as they vie for control of the strait.
Tehran is signaling it may use its Houthi allies in Yemen to shut the Bab el-Mandeb, which leads into the Red Sea, opening a new front against Washington and putting two of the world's most vital shipping arteries at risk.
Around nine Greek-operated LNG tankers, which had sailed into the Gulf via Hormuz in the past week to load cargoes, were stuck inside the strait due to the security concerns, another shipping source said.
Two further tankers have been attacked since July 7 in open waters outside the strait.
U.S. President Donald Trump said in a Truth Social post on Tuesday that the Strait of Hormuz "is open to ALL Ship traffic except for Iran".
The U.S. reimposed its blockade on Iran-linked shipping on Tuesday.
Last week, the U.S. Navy-led Joint Maritime Information Center raised its grading on the risks to ships in the strait to "severe" from "substantial" and one below its highest level, "critical".
The raised risk rating followed attacks on three tankers.
In a note issued by the U.S. Navy after the U.S.-coordinated scheme was launched last month, companies were advised that efforts would be made to advise ship crews "but may not be able to communicate threats to vessels in real-time".
The U.S. military had not provided enough clarity on the risks faced by ships sailing through the Omani route, five of the sources said.
"They have stated that the Strait of Hormuz is 'not closed' and remains available to use," a maritime security source said. "This is making operators nervous and uncertain. Whilst they all have to make their own risk assessments, this is clearly not safe, so why say it is open?"
Greek maritime security company Diaplous said in an advisory on Tuesday that the threat environment remains high and advised shipping companies to pause voyages until Saturday.
MARISKS, another Greek maritime security company, in a separate advisory, also said on Tuesday: "At this stage, there is no assurance that transits through the Strait of Hormuz can be conducted with an acceptable level of safety."
XLE•
