Official moves towards the deployment -- fiercely opposed by China -- of a US missile defence system in South Korea highlight the inherent dangers of disunity in dealing with North Korea's growing military threat.
North Korea said it had successfully tested a miniature hydrogen bomb. If confirmed, this would place it among a small group of countries with such dangerous weapons.
North and South Korean families divided by war for more than 60 years said a final, traumatic farewell after a reunion event that, for most, marked the last time they will ever see each other.
US President Barack Obama and his South Korean counterpart stressed their readiness to "engage" nuclear-armed North Korea Friday, albeit with conditions.
North Korea's foreign minister told the United Nations that a peace treaty was urgently needed to prevent a repeat of the military standoff that rattled Asia two months ago.
North and South Korea agreed to hold a reunion in October for families separated by the Korean War, following all-night talks between their respective Red Cross branches.
North Korean leader Kim Jong-Un said nuclear weapons -- not negotiating skills -- secured what he described as a "landmark" agreement this week with South Korea.