ELSEWHERE IN THE MIDDLE EAST: ISIS claims deadly attack on U.S.-backed forces in Yemen.

A suicide attacker set off a massive car bomb in Yemen’s southern city of Aden on Monday, killing at least 45 pro-government troops who had been preparing to travel to Saudi Arabia to fight Houthi rebels in Yemen’s north, officials said.

The men were at a staging area near two schools and a mosque where they were registering to join the expedition. The Saudis hope to train up to 5,000 fighters and deploy them to the Saudi cities of Najran and Jizan, near the border, Yemeni security officials said. Over 60 wounded were being taken to three area hospitals, they added.

Yemen is shaping up to become as big of a humanitarian disaster as Syria, with 3 million of its population of 25 million displaced in fighting since March of last year.