Iran-backed Houthi rebels said overnight airstrikes targeted the Red Sea island of Kamaran, the Qanawis district north of the port city of Hodeida and Jawf province. The Houthi-run al-Masirah satellite television network blamed Saudi Arabia on Tuesday. The kingdom did not immediately comment. The reported strikes came hours after air raid sirens sounded on Monday in the Saudi capital, Riyadh, where residents heard explosions. Also Tuesday, Qatar’s emir called for greater security cooperation among Gulf countries.