Obama: 'Madmen' must not be allowed to get nuclear material

U.S. President Barack Obama urged world leaders on Friday to do more to safeguard nuclear facilities to prevent “madmen” from groups like Islamic State from getting their hands on a nuclear weapon or a radioactive “dirty bomb.”
Speaking at a nuclear security summit in Washington, Obama said there was a persistent and evolving threat of nuclear terrorism despite progress in reducing such risks.
But he insisted: “We cannot be complacent.”
Obama said no group had succeeded in obtaining bomb material but that al Qaeda had long sought them and cited actions by Islamic State militants behind recent attacks in Paris and Brussels that raised similar concerns.