North Korea has reiterated that it will bolster its nuclear deterrent in response to the ongoing joint military exercises between South Korea and the United States.

The North Korean Foreign Ministry spokesman told the North’s state-run Korean Central News Agency Tuesday that the decision by South Korea and the U.S. to launch the military drills at a time when Pyongyang has made significant calls for a peace treaty is a serious provocation.

The spokesman added that military threats and economic sanctions cannot coexist with dialogue, adding that a nuclear-free Korean Peninsula cannot be established without a resolution on military confrontation.

Earlier on Sunday, or one day before the Key Resolve and Foal Eagle exercises began, the North’s military declared that it would halt all denuclearization efforts.

On Monday, North Korea’s military ordered its Korean People’s Army to be ready for combat, calling the exercise “preparation” for an invasion.