The White House has said that the focus of next week's nuclear summit in Washington is narrow: securing nuclear materials and preventing them from reaching terrorists.

Ben Rhodes, deputy national security adviser for strategic communications, said during a briefing on Friday, "The summit is dedicated to nuclear security and the threat of nuclear terrorism. There's vulnerable nuclear material around the world."

Representatives from 47 countries, the United Nations, the International Atomic Energy Agency and the European Council will begin arriving in Washington Sunday for a series of bilateral meetings and plenary sessions to discuss nuclear security. The summit ends Tuesday.

Rhodes further said that since he was a U. S. senator, Barack Obama has focused on the issue of nuclear security. During a speech in Prague, Czech Republic, a year ago, President Obama outlined his goal to aggressively push non-proliferation, including the goal of securing vulnerable nuclear material, plutonium and highly enriched uranium, in four years.

Rhodes also mentioned, "Probably no one nation is capable of taking the action necessary to secure vulnerable materials worldwide. And no one nation is capable of enacting the security measures necessary" to block illegal transit of the material.

Gary Samore, senior presidential adviser and senior director for non-proliferation, said that separated plutonium and highly enriched uranium are the two materials that can be used for nuclear weapons.

Samore said during the conference call with reporters "If we're able to lock those down and deny them to non-state actors, then we have essentially solved the risk of nuclear terrorism."

Adding he expects some countries to announce their plans for securing loose nuclear material, Samore said that the primary responsibility for securing nuclear materials rests with individual countries, assisted by international protocols. (With Inputs from Agencies)