Pyongyang late Friday threatened to take "regretful and painful" retaliation soon against Seoul as their mutual trust is "shattered" by the latter's failure to stop anti-Pyongyang leaflets from being sent into the North.

Pyongyang dismissed Seoul's promise to stop "defectors" from sending balloons carrying leaflets as "lip service," Jang Kum Chol, director of the United Front Department of the Central Committee of the Workers' Party of the Democratic People's Republic of Korea (DPRK), said in a statement carried by the official Korean Central News Agency (KCNA).

"Their statement sounds like an apology or repentance, and their 'resolution to take counteraction' sounds plausible," Jang said. "But it is hard to clear the doubt that it can be just a brainstorm trick of Chongwadae (the presidential palace) to tide over the present crisis. Because its attitude of repentance is too timid, when compared with the gravity of the crime committed."

The senior official warned that "the times ahead will be truly regrettable and painful" for authorities of the Republic of Korea (ROK).

"The confidence that (we) tried so hard to have in the South Korean (ROK) authorities has been shattered," he added.

In response to the DPRK's strong protest, the ROK government has promised to deal strictly with activists' flying of anti-Pyongyang leaflets into the North and take legislative measures to ban the "hostile act" at the border area.

Jang said the ROK authorities were so far only "paying lip service," and "they have availed themselves of every chance to unleash spurious words while reading others' faces with hesitation."

Seoul could have made "dozens of such laws" since President Moon Jae-in signed the Panmunjom Declaration with DPRK leader Kim Jong Un in April 2018, he said. The declaration called for complete denuclearization of the Korean Peninsula and improving inter-Korean relations.

Read more: 

U.S. and DPRK, a repeated circle of progress and disappointment

DPRK urges U.S. 'to keep its mouth shut' on inter-Korean affairs

Friday was the two-year anniversary of Kim's historic summit with U.S. President Donald Trump in Singapore. But nuclear talks between Washington and Pyongyang have stalled since the second Trump-Kim summit collapsed in Vietnam's Hanoi in February 2019, leading to stalemate in inter-Korean cooperation and renewed tensions on the peninsula. 

Pyongyang announced on Tuesday to cut off all inter-Korean communication lines. The joint liaison office set up in 2018 was shut down by the DPRK a few days earlier. 

Meanwhile, DPRK Foreign Minister Ri Son Gwon said the country sees little use maintaining a personal relationship between its leader and Trump if Washington sticks to hostile policies, the official news agency KCNA reported on Friday. 

The DPRK will continue to build up its military forces to cope with the threats from the U.S., Ri said. 

Commenting on the recent escalation of tensions, Chinese Foreign Ministry spokesperson Hua Chunying on Friday urged Washington to take concrete actions to implement the consensus reached between Trump and Kim two years ago and respond to Pyongyang's legitimate concerns on development and security. 

(With input from Xinhua)