The announcement came as President Donald Trump warned the United States would strike Iran “hard” after a missile attack against US bases in Jordan, reigniting the Middle East conflict after a days-long pause.

An “extortion scheme” backed by Iran’s Revolutionary Guard “forces commercial vessels to purchase mandatory maritime ‘insurance’ to transit the Strait,” the US Treasury Department said in a statement.

“These entities manufacture risk — including the threat of vessel seizures — and then charge commercial vessels for coverage against dangers created by the regime itself,” a parallel State Department statement said.

The sanctions target the Persian Gulf Marine Insurance Company and the HormuzSafe Marine Services Authority, which, according to Washington, are linked to Iran’s Islamic Revolutionary Guard Corps.

Washington also sanctioned eight companies operating ships that it accused of transporting Iranian crude oil and petrochemicals to China and the United Arab Emirates, in violation of other US sanctions.

These ships are “part of Iran’s ‘shadow fleet,’ which the regime relies on to evade sanctions,” the State Department said.

“With its economy in freefall and inflation in the triple digits, the regime is desperate for cash,” Treasury Secretary Scott Bessent was quoted as saying.

After hostilities with Washington resumed on July 7, Iran once again blocked the Strait of Hormuz — a crucial shipping lane for the global energy trade — claiming the right to impose transit fees on ships and allowing passage only along the route hugging its coastline.

The United States, for its part, has imposed a blockade on Iranian ports.

Approximately 20 per cent of the world’s oil and liquefied natural gas passed through the Strait of Hormuz before the war.