The Latest: World leaders gather for nuclear security summit

The Latest on the Nuclear Security Summit convened by President Barack Obama:

9:45 a.m.

Dozens of world leaders are gathering in the nation's capital for a summit on nuclear security hosted by President Barack Obama.

It's the fourth such summit Obama has held focused on preventing nuclear terrorism and countering nuclear smuggling. This one follows deadly attacks in Paris, California, Belgium, Pakistan and elsewhere, heightening fears about what extremists could do using nuclear material.

On the margins of Thursday's sessions, Obama plans a three-way meeting with Japanese Prime Minister Shinzo Abe (shin-zoh ah-bay) and South Korean President Park Geun-hye (goon-hay). Both U.S. allies are deeply concerned about recent nuclear tests and a rocket launch by neighboring North Korea.

Obama was also holding one-on-one meetings with Chinese President Xi Jinping (shee jihn-peeng) and French President Francois Hollande.

Leaders are expected at the White House for a working dinner with Obama.