The U.S. has warned North Korea of a strong punishment if it conducts a nuclear test, as Washington and a United Nations¡¯ watchdog agency have said signs indicate Pyongyang could soon set off its first atomic device since 2017.

¡°There would be a swift and forceful response to such a test,¡± Deputy Secretary of State Wendy Sherman said in Seoul on Tuesday.

¡°Any nuclear tests would be in complete violation of U.N. Security Council resolutions,¡± she said, adding it ¡°would be very destabilizing to the world security.¡± Sherman didn¡¯t elaborate on specific measures but suggested the U.S. could work with its allies to levy punishments.