Marine Corps General Joseph Dunford, Chairman of the Joint Chiefs of Staff and South Korean Defense Minister Song Young-Moo.(Photo: SONG KYUNG-SEOK / POOL, EPA)

He held separate talks on Monday with South Korean Defence Minister Song Young-moo and his counterpart Lee Sun-jin, during which they also discussed strengthening the Seoul-Washington alliance. Gen. Dunford reiterated Washington’s commitment to defend its ally Seoul and offer extended deterrence against North Korea's threats in the event of war.

The same day, North Korea’s ambassadors returned to Pyongyang for a meeting amid strong international protests against its nuclear and missile programs.