CEUTA, Spain—Authorities in Ceuta, the Spanish enclave at the center of a humanitarian crisis and a diplomatic dispute between Morocco and Spain, said Thursday that no migrants crossed overnight into the city after security forces in the neighboring north African kingdom tightened the shared border. Security forces clashed well into the night with dozens of mostly young men who had gathered in Fnideq, the Moroccan town across the border from Ceuta, hoping to follow the thousands who reached European soil in previous days. The scuffles broke out when police tried to break up the groups of people who had gathered and set fire to a barricade blocking the street. The police moved back but later dispersed the group. In previous days, the border between Morocco and Ceuta became porous following warnings from the Moroccan government to Spain that it would face consequences over Madrid’s decision to provide coronavirus treatment to …