(CNN) North Korea has threatened to renege on commitments made to the United States on denuclearization, accusing the Trump administration of breaching the "spirit" of the negotiations by planning joint military exercises with South Korea.

North Korea's foreign ministry said in a statement Tuesday that the military drills were a "rehearsal for war" and broke promises US President Donald Trump made when he met Kim Jong Un at a summit in Singapore in June 2018.

"With the US unilaterally reneging on its commitments, we are gradually losing our justifications to follow through on the commitments we made with the US as well," the statement said.

"It is crystal clear that it is an actual drill and a rehearsal of war aimed at militarily occupying our Republic by surprise attack and rapid dispatch of large-scale reinforcements," it said. "The suspension of joint military exercises is what President Trump, Commander-in-Chief of the US, personally committed to at the DPRK-US summit talks in Singapore under the eyes of the whole world."

"Our discontinuation of the nuclear and ICBM tests and the US suspension of joint military exercises are, to all its intents and purposes, commitments made to improve bilateral relations. They are not a legal document inscribed on a paper."