By Phil Stewart and Timour Azhari WASHINGTON/BAGHDAD (Reuters) -Missile attacks in Syria, Lebanon, Iraq and Yemen on Saturday threw into sharp focus the increasing risk of the war in Gaza triggering a wider regional conflict pitting Iran and its allies against Israel and the United States. Iran said five of its Revolutionary Guards were killed in a missile strike on a house in Damascus which it blamed on Israel, and security sources in Lebanon said an Israeli strike there killed a member of Iran-backed Hezbollah. Later on Saturday, missiles and rockets launched by Iran-backed militants in Iraq…