US warns shipping firms they could face sanctions over Strait of Hormuz tolls

Cargo ships are seen at sea near the Strait of Hormuz (Fatima Shbair/AP)

The United States is warning shipping companies that they could face sanctions for making payments to Iran to safely pass through the Strait of Hormuz.

The alert posted on Friday by the US Office of Foreign Assets Control adds another layer of pressure in the standoff between the US and Iran over control of the Strait of Hormuz.