By Phil Stewart, Idrees Ali and Mohammed Ghobari WASHINGTON/ADEN, Yemen (Reuters) – U.S. and British warplanes, ships and submarines struck across Yemen overnight in retaliation against Iran-backed Houthi forces for attacks on Red Sea shipping, a widening of regional conflict triggered by Israel’s war in Gaza. Witnesses confirmed explosions throughout Yemen, saying raids targeted a military base adjacent to Sanaa airport, a military site near Taiz airport, a Houthi naval base in Hodeidah and military sites in Hajjah governorate. “These targeted strikes are a clear message that the United State…