The Democratic People's Republic of Korea (DPRK) said the Republic of Korea (ROK) and the United States are risking a "huge security crisis" by choosing to escalate tensions, the Korean Central News Agency reported on Wednesday citing a top Workers' Party official.

Kim Yong Chol, a general and politician who played a leading role during the historic summits between DPRK leader Kim Jong Un and former U.S. President Donald Trump, criticised the ROK and the U.S. for responding to Pyongyang's goodwill with "hostile acts."

On Wednesday, Kim Yong Chol singled out the ROK for going ahead with the drills with the U.S. and said the DPRK will "make clear of the cost they should pay" for choosing their alliance with Washington over peace between the Koreas. 

"We will have them realize what a dangerous choice they made and how close they are to a huge security crisis by making the wrong choice," he said in a statement carried by state news agency KCNA.

The statement comes a day after Kim Yo Jong, sister of leader Kim Jong Un, warned Seoul and Washington over annual joint military drills set to begin this week.

The ROK and the United States are set to hold computer-simulated exercises next week, but preliminary training began on Tuesday, military sources told Reuters.

Kim Yo Jong said U.S. military actions showed Washington's talk of diplomacy was a hypocritical cover for aggression and that peace would only be possible if it dismantled its military force in the South.

Meanwhile, Seoul said Pyongyang did not answer routine calls on inter-Korean hotlines on Tuesday, hours after Kim Yo Jong's warning.

The two Koreas typically check in over the hotlines twice a day, and DPRK officials answered morning calls as usual on hotlines maintained by ROK's military and those used by the unification ministry, which handles relations with Pyongyang. 

But the South's calls in the late afternoon were unanswered, the unification and defense ministries said.

(With input from Reuters)