WASHINGTON – Still reeling from attacks in Brussels and Paris, world leaders are wrestling this week with the chilling prospect of the Islamic State group or other extremists unleashing a nuclear attack on a major Western city.
Preventing terrorists from obtaining nuclear materials is the central focus as President Barack Obama hosts leaders from roughly 50 countries for a nuclear security summit starting Thursday. Despite three previous summits and six years of Obama’s prodding, security officials warn that the ingredients for a nuclear device or a “dirty bomb” are alarmingly insecure.
 “We know that terrorist organizations have the desire to get access to these raw materials and to have a nuclear device,” said Ben Rhodes, Obama’s deputy national security adviser. Still, the White House said there was no indication of an imminent plot.
Decades after the Cold War, the threat of a nuclear war between superpowers has given way to growing concerns about non-state actors operating in North Africa and in Yemen.
The havoc such an attack could wreak in an urban area like New York or London is concerning enough that leaders scheduled a special session on the threat during the two-day summit. U.S. officials said the leaders would discuss a hypothetical scenario about a chain of events that could lead to nuclear terrorism.

Source: AP, March 30, 2016