The U.S. envoy to Saudi Arabia condemned as "unacceptable" drone attacks on Saudi oil facilities on Saturday which were claimed by Yemen's Iran-aligned Houthi movement. "The U.S. strongly condemns today's drone attacks against oil facilities, in Abqaiq and Khurais. These attacks against critical infrastructure endanger civilians, are unacceptable, and sooner or later will result in innocent lives being lost, the U.S. mission quoted Ambassador John Abizaid as saying, according to Reuters.