On April 5 , 2009 , in Prague , U.S. President Barack Obama had presented a three-part strategy to address the international nuclear threat . The strategy consisted 1 . ) proposing measures to reduce and eventually eliminate existing nuclear arsenals ; 2 . ) strengthening the Non-proliferation Treaty and halting proliferation of nuclear weapons to additional states ; and 3 . ) preventing terrorists from acquiring nuclear weapons or materials . The President stated in his Prague speech that nuclear terrorism is the most immediate and extreme threat to global security . He announced an international effort to secure vulnerable nuclear materials within four years , break up black markets , detect and intercept materials in transit , and use financial tools to disrupt illicit trade in nuclear materials . In the 2009 L'Aquila Summit held in Italy Obama formally announced his plan to host a Global Nuclear Security Summit in March 2010 for this purpose
L'Aquila Summit
35th G8 summit
2010 Nuclear Security Summit