North Korea Warns of 'Strike' Against U.S. 'If Necessary'

North Korea warned on Tuesday that it can "strike" whenever necessary if faced with a "nuclear threat" from the U.S., which is currently carrying out annual military exercises with South Korea.

The rare comments were made by North Korean Foreign Minister Ri Su Yong at the United Nations-sponsored Conference on Disarmament this week, and immediately received criticism from the United States.

Yong said at the conference that the U.S. military drills with South Korea are "unprecedentedly provocative in nature and have an especially high possibility of sparking off a war."

"The DPRK (Democratic People's Republic of Korea) cannot but bolster its nuclear deterrent capability to cope with the ever-increasing nuclear threat of the U.S.," Yong said at the conference, held in Geneva. "Now the DPRK has the power of deterring the U.S. and conducting a pre-emptive strike as well, if necessary."

North Korea's warning comes shortly after a report by the U.S.-Korea Institute at Johns Hopkins University's School of Advanced International Studies which warned that the isolated Asian country may have stockpiled weapons over the past several years.

The report caused a response from Sung Kim, U.S. Special Representative for North Korea Policy, who said the U.S. is "deeply concerned" over the possibility of a nuclear weapon stockpile in North Korea.

Kim said that while he cannot comment on the findings of the report, "obviously we are deeply concerned about the fact that the North Koreans are continuing to advance their nuclear capabilities; we know that they are continuing to work on their nuclear program."