The Nuclear Security Summit is underway.

FOX's Jon Decker has more from the White House:

Faced with a North Korean regime bent on developing a nuclear-armed long-range missile, President Obama met with his counterparts from Japan and South Korea, to make clear that the international community will vigorously enforce recently-passed sanctions by the U.N. Security Council:

(President Obama) "We are united in our efforts to deter and defend against North Korean provocations."

President Obama will also meet with Chinese President Xi Jinping about North Korea. China has been criticized in the past for not enforcing previous U.N. sanctions against Pyongyang.

At the White House, Jon Decker, FOX News.