In a sign the conflict with Iran is expanding to the Red Sea, Iranian-backed Houthis claimed responsibility for an attack on Saudi oil tankers.

The president proclaimed that any type of Iranian attack on vessels traveling through the waterway would trigger a corresponding American strike on key infrastructure.

The U.S. military announced the 13th night of strikes Thursday against Iran as clashes escalate over shipping routes. The attacks came after Yemen’s Iran-backed Houthi rebels said they attacked two Saudi oil tankers in the Red Sea,

The U.S. launched its 12th straight night of attacks on Iran. New threats today mean the Iran war could further disrupt the oil market.