By Greg Robb
WASHINGTON (MarketWatch) -- President Barack Obama said Tuesday that his biggest worry remains a scenario in which terrorists would be able to obtain dangerous nuclear materials and set off a bomb in New York City. Asked at a press conference if Russia was the number one security threat to the U.S., Obama replied: "I continue to be much more concerned when it comes to our security with the prospect of a nuclear weapon going off in Manhattan." Earlier, Obama met with world leaders in the Hague to press for new steps to secure the world's nuclear material. Belgium and Italy have agreed to remove excess supplies of nuclear material and Japan announced it would destroy hundreds of kiograms of nuclear material, Obama said.
