American warships didn't fire a shot, but they still turned six vessels around in the first day of a new US blockade targeting Iranian ports, a US official said Tuesday. Five of the ships were carrying oil; the cargo of the sixth wasn't immediately known, NBC News reports. Two tankers reversed course within the first two hours after the measure kicked in Monday morning, according to the official, who said no boardings took place. US Central Command said the blockade "completely" cuts off Iran's international sea trade, CNBC reports. China on Tuesday called the blockade a "dangerous and irresponsible" escalation.
President Trump announced the blockade Sunday after talks with Tehran failed to end the war, effectively freezing traffic through the Strait of Hormuz and helping drive up oil prices. The Pentagon is enforcing the move with more than a dozen ships and over 100 fighter and surveillance aircraft, focusing its assets in the Gulf of Oman rather than the more vulnerable Persian Gulf. Vessels identified as leaving Iranian ports are warned by radio that they're violating the blockade and ordered back to Iranian harbors. None have defied those orders so far, but the official said US forces are authorized to use air or naval firepower if a ship refuses to comply. Pre-blockade traffic in the Strait of Hormuz was already at a fraction of its normal volume due to the war, Reuters reports.