WASHINGTON — World leaders concluding a 47-nation nuclear security conference on Tuesday endorsed President Barack Obama's call for securing all of the globe's vulnerable nuclear materials within four years — but offered few specifics for achieving that goal.
Aiming for quick action, the United States declared that the Obama administration had submitted to Congress legislation to bring U.S. laws into line with two treaties: one to crack down on potential nuclear terrorism and one on the physical protection of nuclear materials.
Obama had called the summit to focus world attention on keeping such dangerous materials out of terrorist hands, a peril he termed the greatest threat facing all nations.
Addressing the conference, Obama framed the problem as a "cruel irony of history" — nuclear dangers on the rise, even after the end of the Cold War and decades of fear stoked by a U.S.-Soviet arms race. A terrorist group in possession of plutonium no bigger than an apple could detonate a device capable of inflicting hundreds of thousands of casualties, he said.
"Terrorist networks such as al-Qaida have tried to acquire the material for a nuclear weapon, and if they ever succeeded, they would surely use it," he told the opening session, which convened under tight security at the Washington Convention Center. "Were they to do so, it would be a catastrophe for the world, causing extraordinary loss of life and striking a major blow to global peace and stability."
The summit countries said they would cooperate more deeply with the United Nations and its watchdog arm, the International Atomic Energy Agency. They also said they would share information on nuclear detection and ways to prevent nuclear trafficking.
In the joint work plan spelling out specific actions to be taken, the summit countries said they would "work together to achieve universality" of the International Convention for the Suppression of Acts of Nuclear Terrorism, but there was no mention of specific additional countries formally ratifying the convention. They also underscored the importance of a 2005 amendment to the Convention on the Physical Protection of Nuclear Material.
The U.S. also committed to requesting an "advisory mission" from the International Atomic Energy Agency to review physical security at a nuclear facility of the National Institute of Standards and Technology.
Lurking in the background at the nuclear security summit was a problem some see as equally worrisome: Iran's alleged pursuit of a nuclear weapon. Iran, which was not invited to the conference, denies it intends to build an atomic bomb, and despite widespread concern about its intentions, Obama is having difficulty getting agreement on a new set of U.N. sanctions against Iran.
The summiteers announced that a follow-up nuclear security conference will be held in South Korea in 2012.
President Lee Myung-bak told reporters that North Korean leader Kim Jong Il will not get an invitation until the North gives up its efforts to build a nuclear arsenal.
North Korea's efforts — and its withdrawal from the Nuclear Non-Proliferation Treaty that sets the rules of the road for nuclear technology — kept it out of the Washington summit. Syria, which is suspected by the U.S. and others of harboring nuclear weapons ambitions, also was not invited.
As an example of the collective action called for by Obama, officials of the U.S., Canada and Mexico announced an agreement to work together, along with the U.N.'s nuclear watchdog agency, to convert the fuel in Mexico's research reactor from highly enriched uranium to a lower-enriched fuel that would be much harder to use in the manufacturing of a nuclear weapon.
Mexico further agreed that once the fuel is converted, it will get rid of all its highly enriched uranium. That follows Ukraine's announcement on Monday that it, too, will ship all its highly enriched uranium to protected storage outside its borders — possibly to Russia or the U.S.
U.S. officials touted their completion of a long-delayed agreement with Russia on disposing of tons of plutonium from Cold War-era weapons. Each country will complete and operate facilities to dispose of at least 34 tons of plutonium by using it as fuel in civilian power reactors to produce electricity, although it will not start until 2018; monitors and inspectors will ensure against cheating.
The State Department said the combined 68 tons of U.S. and Russian plutonium represents enough for about 17,000 nuclear weapons. The deal was signed Tuesday at the summit by Secretary of State Hillary Rodham Clinton and Russian Foreign Minister Sergey Lavrov.
British Foreign Secretary David Miliband, in his remarks to the conference, stressed the importance of protecting nuclear-related information.
"We must keep the science as well as the substance of nuclear materials out of terrorist hands," he said, according to a transcript provided by British officials.