Secretary of State Rex Tillerson stressed strategic and economic partnerships in a joint address with Saudi Arabian Foreign Minister Adel bin Ahmed Al-Jubeir in Riyadh Saturday, saying it was a "historic moment" in U.S.-Saudi relations.Accompanying President Donald Trump on his first trip abroad as commander-in-chief — and hours after the administration announced some $109 billion in arms sales to Saudi Arabia and $350 billion in direct U.S.