The head of the U.N.¡¯s nuclear watchdog has warned that North Korea¡¯s atomic program has grown ¡°exponentially¡± since 2009, emphasizing the urgent need for presidential-level diplomacy to reengage with a country that has gone ¡°completely off the charts¡± with its nuclear arsenal.

Speaking Tuesday at a Council on Foreign Relations event in Washington, Rafael Grossi, director-general of the International Atomic Energy Agency, said Pyongyang¡¯s program is no longer limited to the nuclear complex at Yongbyon but also involves the Kangson uranium enrichment plant as well as ¡°a second and perhaps a third enrichment facility being built at the moment.¡±

¡°It¡¯s a reprocessing campaign, which is ongoing as we speak,¡± the IAEA chief said.