President Obama: Risks of nuclear attacks have risen

WASHINGTON (AP) — President Barack Obama told assembled leaders at the 47-country Nuclear Security Summit today the risk of nuclear attack — not by an enemy nation, but from terrorists — was on the rise despite the end of the Cold War.

In his opening address to the first full day of the summit, Obama described the new nuclear reality as a "cruel irony of history." He called the conference with the goal of locking down all nuclear materials worldwide in four years.

"The risk of a nuclear attack has gone up," Obama said, as terrorist organizations like the al-Qaida network try to get their hands on nuclear materials.

By Monday night, when Obama hosted assembled presidents and prime ministers for a dinner, the summit had already paid early dividends: China's agreement to work with the U.S. on possible sanctions against Iran and Ukraine's decision to rid itself of nuclear bomb-making materials.