WASHINGTON - The US Navy is using robots to clear underwater mines planted by Iran in the Strait of Hormuz, the Wall Street Journal reported on Sunday.

A demining operation combining manned and unmanned systems is adopted by the US military to remove the mines laid by Iran, using both surface and underwater drones equipped with sonar detectors, a US defense official was quoted as saying.

US President Donald Trump said on Friday on his Truth Social platform that "Iran, with the help of the USA., has removed, or is removing, all sea mines!" Iran did not respond to the claim.

After Iran re-closed the strait following a brief opening, 35 outbound vessels have turned back over 36 hours, according to a report by Britain-headquartered maritime analytics company Windward.

Iran tightened control over the strait after the United States and Israel launched joint attacks on the country on Feb. 28. The United States also imposed a naval blockade on the strait following its failed negotiations with Iran in Islamabad, Pakistan.