CNN Report: Over 100 U.S. military advisers are on Saudi soil, feeding intelligence and targets to Saudi forces in the operation against the Houthis. The U.S. is providing geospatial targeting and a tool that lets officers track the battlefield in real time, but is not joining strikes or refueling.

American officials now believe hundreds of Revolutionary Guards officers are inside Yemen. One assesses the Iranian officers are working with the Houthis to eventually close the Bab al-Mandab strait, a move CNN earlier described as Tehran's "doomsday weapon" if talks with the U.S. collapse.