North Korea struck a pessimistic tone after the collapse of a two-day summit between Kim Jong Un and Donald Trump, hardening its stance with a warning by a top diplomat that Kim may have "lost the will" to reach an agreement on curtailing his country's nuclear program.

During a rare news conference by North Korean officials, Foreign Minister Ri Yong Ho disputed Trump's claim that Kim had demanded a complete removal of all economic sanctions, insisting that his nation had "offered a realistic proposal" to begin the process of denuclearization.

North Korean Vice Foreign Minister Choe Son Hui told reporters the "U.S. not accepting our proposal is missing an opportunity that comes once in a thousand years."