**President Barack Obama has said the biggest threat to US security is the possibility of a terrorist organisation obtaining a nuclear weapon.**Speaking ahead of a nuclear security summit in Washington, he said leaders from 40 countries would have to focus on how to secure nuclear material.
Groups like al-Qaeda would have “no compunction” at using nuclear devices, he said.
The nuclear summit is due to begin on Monday.
“The single biggest threat to US security, both short-term, medium-term and long-term, would be the possibility of a terrorist organisation obtaining a nuclear weapon,” Mr Obama said.
"This is something that could change the security landscape in this country and around the world for years to come.
“If there was ever a detonation in New York City, or London, or Johannesburg, the ramifications economically, politically and from a security perspective would be devastating.”
Last Thursday, President Obama and Russian President Dmitri Medvedev signed a new Strategic Arms Reduction Treaty reducing each country’s deployed nuclear arsenal to 1,550 weapons.
Earlier in the week, Mr Obama approved a new nuclear policy for the United States, saying he planned to cut the nuclear arsenal, refrain from nuclear tests and not use nuclear weapons against countries that did not have them.This article is from the BBC News website. © British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.