U.S. Treasury sanctions chief David Cohen held talks with senior South Korean officials on Wednesday on ways to beef up punitive sanctions against North Korea for its recent nuclear test and exhorted the North to tread a \"better path.\" Cohen, the U.S. under secretary of the treasury for terrorism and financial intelligence, flew to Seoul from Tokyo where he discussed the same topic with Japanese officials. He is set to visit China later Wednesday. Cohen separately met with Lim Sung-nam, Seoul\'s chief nuclear envoy, and South Korean First Vice Foreign Minister Kim Kyou-hyun earlier in the day.