Iran's joint military command warned Thursday that all oil tankers moving through the Strait of Hormuz must use its approved routes or face a "forceful response", ratcheting up tensions again over a waterway crucial for international energy supplies. The strait, the narrow mouth of the Persian Gulf, has emerged as one of the top issues in negotiations seeking a permanent end to the Iran war. The statement from the Khatam al-Anbiya military command, reported by Iranian state television, comes after both US and Iranian diplomats met with mediators Wednesday in Qatar.