NATO chief condemns North Korea nuclear test

NATO's secretary-general has strongly condemned North Korea's sixth nuclear test, calling it "yet another flagrant violation of multiple U.N. Security Council resolutions."

Jens Stoltenberg also said in a statement that "NATO is concerned by Pyongyang's destabilizing pattern of behavior, which poses a threat to regional and international security."

He called on North Korea to "immediately cease all existing nuclear and ballistic missile activities in a complete, verifiable, and irreversible manner, and re-engage in dialogue with the international community."

North Korea's nuclear test Sunday was apparently its most powerful yet. The country's state-controlled media say it was a thermonuclear device and a "perfect success."