India, July 24 -- Yemen's Iran-backed Houthi rebels said they attacked two Saudi oil tankers in the Red Sea on Thursday, potentially opening a new front as the US military conducted its 12th night of strikes against Iran.

The Houthis have threatened to shut down another key trade route, with the world economy already reeling from Iran's closure of the Strait of Hormuz. Iran and the US have meanwhile stepped up their attacks as they vie for control of the strait, through which a fifth of the world's oil and gas passed in peacetime, setting off a scramble for alternative routes.

US President Donald Trump threatened "major military punishment" against the Houthis if their attacks on ships continue. "If they do this again, the US will hold ...