The commander of US forces in the region said his fleet had destroyed six small Iranian boats, which Iran also denied. Iranian media quoted a military commander as saying US forces targeted civilian boats, killing five civilians.
Iran also said on Monday it had fired on a US warship approaching the strait, forcing it to turn around. Iranian officials later described the fire as warning shots.
Reuters could not independently verify the full situation in the strait on Monday as the warring sides issued contradictory statements.
South Korea reported one of its merchant ships, HMM Namu, in the strait suffered an explosion and fire in its engine room, though no one aboard was hurt. A South Korean government spokesperson said it was unclear if the fire was caused by an attack.
Also on Monday, the British maritime security agency UKMTO reported two ships had been hit off the coast of the UAE, and the Emirati oil company ADNOC said one of its empty oil tankers was hit by Iranian drones.