By Timothy Gardner
WASHINGTON (Reuters) - Starting in May more than 150 countries will be legally bound to strengthen their protection of nuclear facilities and to cooperate in finding and recovering stolen or smuggled nuclear material, security officials said on Friday.
An amendment to the decade-old Convention on Physical Protection of Nuclear Material was ratified after Nicaragua and Uruguay became the 101st and 102nd signatories, reaching the two-thirds of convention members required to make it legal.
Yukiya Amano, the head of the International Atomic Energy Agency, said in a statement that the amendment "will help reduce the risk of a terrorist attack involving nuclear material, which could have catastrophic consequences."
The measure, which will go into force in 30 days, makes it legally binding for countries to protect nuclear facilities, as well as the domestic use, storage and transportation of nuclear material. States would be required to minimize any radiological consequences of sabotage and to prevent and combat such offenses.
President Barack Obama's National Security Advisor Susan Rice said the agreement is a "cornerstone of the global nuclear security architecture," and that the administration will "urge all countries who have not yet ratified this treaty to do so as soon as possible."
About 10 countries including Pakistan, Azerbaijan and Kuwait signed the amendment last week ahead of a nuclear summit hosted by Obama in Washington.
Amano said before last week's summit that more work was needed in making the amendment universal, which would help ensure that all countries with nuclear capabilities - including North Korea - adhered to the measure, not just those countries that had ratified it.
(Reporting by Timothy Gardner; editing by Grant McCool)