According to Reuters, U.S. President Donald Trump told his Turkish counterpart Tayyip Erdogan that he wanted the issue over Ankara’s procurement of air defense systems to be resolved without damaging bilateral ties. Turkey and the United States have been at odds over Ankara’s purchase of Russian S-400 defense systems, a move Washington has warned would trigger U.S. sanctions. Turkey has so far dismissed the warnings and said it would not turn back from the deal.