MUNICH - Russian Prime Minister Dmitry Medvedev said on Saturday that only regular cooperation between Russia and the United States can lead to a normalization of the situation in Syria."I want to emphasize that regular cooperation between Russia and the United States will be crucial," Medvedev said in a speech at a security conference in Munich. "And I mean regular - every day."Medvedev also said he saw no need to scare anyone with a ground operation in Syria. It was not immediately clear to what he was referring.