BRUSSELS—U.S. President Joe Biden and Turkish President Tayyip Erdogan sounded upbeat after their first face-to-face talks on Monday, although they did not announce major breakthroughs in the relationship between the two allies, at odds over Russian weapons, Syria, Libya and other issues. “We had a positive and productive meeting, much of it one-on-one,” Biden told a news conference after their meeting in Brussels. “Our teams are going to continue our discussions and I’m confident we’ll make real progress with Turkey and the United States,” he added. Erdogan characterized his talks with Biden on the sidelines of a NATO summit as “productive and sincere.” “We think that there are no issues between U.S. and Turkey relationship that are unsolvable and that areas of cooperation for us are richer and larger than problems,” he said. Despite their publicly optimistic tone, neither provided any details on how exactly they would mend the relationship …