North Korea said on Tuesday it would boost its nuclear capability in response to what it considers "continuing U.S. military threats and provocations," the Yonhap news agency said, citing the North''s official Korean Central News Agency.

The statement issued by the North Korean Foreign Ministry comes a day after South Korea and the United States launched a 10-day annual joint exercise, dubbed Key Resolve/Foal Eagle, on the Korean Peninsula.

"North Korea will continue bolstering up its nuclear deterrent as long as the U.S. military threats and provocations go on," Yonhap quoted an unidentified foreign ministry spokesman as saying.

The reclusive communist state also said the ongoing exercises near its borders amounted to a rehearsal for a preemptive attack on the country and vowed to suspend all military dialogue with the U.S. and the South during the period.

Although both South Korea and the United States defended the Key Resolve/Foal Eagle military drills as purely defensive, North Korea said it put its armed forces on full military alert.

North Korea and the U.S. are formally still at war as the Korean War ended in 1953 with an armistice and no peace treaty has since been signed.

The current confrontation could jeopardize the diplomatic efforts aimed at the resumption of dialogue on the denuclearization of the Korean Peninsula, Yonhap said.