The three leaders urged the international community to"vigilantly enforce" tougher U.N. sanctions against North Korea.North Korea was also at the top of the agenda when Mr. Obamamet later with Chinese President Xi Jinping._______________ 三国领导人敦促国际社会"警惕地执行"联合国对朝鲜实施的更为严厉的制裁.朝鲜问题也是奥巴马稍后会见中国国家主席习近平时的首要议题.______________
