South Korea, the U.S. and Japan, meanwhile, held three-way defense talks Sunday morning in Singapore.
Seoul's defense minister, Song Young-moo met for about an hour with his counterparts James Mattis and Itsunori Onodera on the sidelines of the Shangri-La Dialogue, Asia's biggest security forum.
Speaking to reporters before the closed-door talks began,... Song called for greater military cooperation to achieve the denuclearization of North Korea.
In his remarks, Mattis said the only way North Korea will get relief from international sanctions is if it takes verifiable and irreversible steps to denuclearize.
And Japan's defense minister said the three countries need to strengthen their military cooperation, but also called on North Korea to cooperate in resolving long-standing humanitarian issues... like the Japanese nationals abducted by the regime.