Iran has effectively shut the Strait of Hormuz, a crucial global waterway for oil and gas transport, since it came under attack from US and Israeli air strikes on 28 February.
More than a dozen US warships and some 10,000 US military personnel are now enforcing the blockade against vessels of any country entering or leaving Iranian ports, starving Iran of a vital economic lifeline.
It is aimed at putting pressure on Tehran by targeting two of the country’s major money sources: oil revenue and the significant tolls Iran demanded from ships for passage through the critical waterway.
US Central Command (Centcom), which has responsibility for US military activity in the Middle East and parts of Central Asia, said six merchant vessels had “complied with direction” from American forces to turn around and return to Iranian ports in the first 24 hours of the blockade.