Iran’s main oil-loading terminals have remained empty for weeks, adding to signs that a US naval blockade of the country is throttling Tehran’s exports.

Empty supertankers are heading to Egypt’s Mediterranean port of Sidi Kerir to collect Saudi Arabia’s crude, a signal of wariness among some shipowners about sailing closer to Houthi-threatened waters.

Millions of barrels of Saudi Arabian crude are still being shipped from the nation’s Red Sea coast to the global market, despite threats and attacks by Yemen’s Houthi militants against the kingdom’s shipping that have the potential to further destabilize the global oil trade.