The United States has issued a fresh warning to global shipping firms, cautioning that any payments made to Iran for safe passage through the Strait of Hormuz could trigger sanctions. 

The notice, released Friday by the Treasury Department’s Office of Foreign Assets Control, signals a sharp escalation in tensions over one of the world’s most critical energy corridors.

The Strait of Hormuz, located at the entrance to the Persian Gulf, typically carries around 20% of global oil and natural gas shipments. 

Since late February, however, the route has been effectively disrupted following attacks and threats against commercial vessels. The incidents began after the U.S. and Israel-led military launched attacks on February 28.

In recent weeks, Iran has reportedly offered certain ships alternative routes closer to its coastline, in some cases charging fees for safe transit. U.S. officials are saying that such arrangements could violate sanctions regardless of the form of payment.

U.S. forces have enforced a naval blockade since April 13 targeting Iranian ports, aiming to cut off a key source of revenue for Tehran as it grapples with economic strain.

U.S. Central Command said 48 commercial ships were directed to reverse course instead of risking passage through the disputed waters.