n 2005, North Korea agreed to the agreement of Landmark in which they return nuclear spirits for economic and political aid. But they destroyed cooling tower at Yongbyon in 2008 going false towards a statement of aid.
The US never believed that Korea has closed its efforts for a nuclear bomb, Korea in 2012 announced its nuclear activities for food US aid but this came to nothing.
South Korean President said it is act of self-destruction, the US warned of serious cosequences.
North Korea has banned from any nuclear test but they hit five times since year 2006.
Japan’s President also said this attack gave threat to Japan and severely undermines the peace.