The United States announced fresh sanctions on Friday against three Iranian foreign currency exchange companies, aiming to cut off what officials described as Tehran’s “financial lifelines” fueling instability in the Middle East.

In a separate warning, the US Treasury Department cautioned that any payments made to Iran’s government for safe passage through the Strait of Hormuz could trigger sanctions.

The strategic waterway, vital for global energy shipments, has been effectively blocked by Tehran since late February following joint US-Israeli strikes on Iranian targets.