The annual military drills conducted by South Korea and the US were “frantic war exercises,” North Korea said Tuesday, warning of consequences.

“The US and the Republic of Korea have once again launched provocative, large-scale joint military exercises that amplify the unpredictability of the situation in the Korean Peninsula,” North Korea’s Ministry of Defense said in a statement carried by the official state media, the Korean Central News Agency, referring to South Korea's formal name.

The Freedom Shield joint exercises kicked off Monday, with a focus on tackling North Korean nuclear threats. Strategic assets of the US such as nuclear-powered aircraft carriers are likely to be deployed for the drills, to run through March 14.

The Defense Ministry in Pyongyang said that on the Korean Peninsula the atmosphere has become ripe for nuclear war, which could be “triggered by a single spark.” “Such large-scale war drills conducted by the world’s largest nuclear power and dozens of follower countries can not by any measure be seen as ‘defensive,’” it added.

“We strongly condemn the reckless military exercises by the US and the Republic of Korea, which are further escalating military threats against sovereign countries,” it said, claiming that the joint drills amount to “attempts of an invasion.”

The ministry warned the US and South Korea to “cease any further provocative and destabilizing actions,” stressing that they will be “made to pay a hefty price for their wrong choices.”

“We will continue to keep a close eye on the adventurist actions of our enemies, and we will continue our responsible military activities to control the unstable security environment in the Korean Peninsula,” the ministry said.

In a departure from earlier customs, North Korea has begun referring to the South by its official name, the Republic of Korea, since July last year. Intelligence authorities in Seoul said in a response to The Korea Herald that the use of South’s official name in Pyongyang’s official statements was “intended to be derisive.”