The Democratic People's Republic of Korea (DPRK) on Thursday said the United States has no standing to comment on inter-Korean affairs, and said it is in Washington's interest to stay quiet if it wants a successful presidential election, state news agency KCNA reported. 

The statement comes after the U.S. State Department said it was disappointed at the DPRK for suspending communication hotlines with the Republic of Korea (ROK) on Tuesday. 

"I am sick of the two-sidedness of the U.S. who is eager to stop the inter-Korean relations when it shows sign of progress, but acts up when it seems to sour," Kwon Jong Gun, director-general for U.S. affairs at the DPRK's Foreign Ministry, said in an interview with KCNA. 

"Not only would this be in the interest of the United States, but also be beneficial for a successful presidential election ahead," Kwon said, telling the U.S. "to keep its mouth shut" unless it wants to go through "something terrible."

The DPRK said on Tuesday it would sever hotlines with the ROK as the first step toward shutting down all contact after days of lashing out at Seoul for not stopping "defectors from the North" from sending anti-Pyongyang leaflets to the DPRK. 

ROK's presidential Blue House said on Thursday that the government will thoroughly clamp down on the dispersion of anti-DPRK leaflets and materials and any violation will be sternly dealt with according to domestic law. 

The government urges local civic groups to thoroughly follow relevant laws, Kim You-geun, first deputy director of the Blue House National Security Office (NSO), told reporters.

The civic groups delivered anti-DPRK propaganda leaflets across the border by flying balloons into the air or setting the sealed plastic bottles into the ocean near the border areas.

A day earlier, Seoul said it would take legal action against two organizations that conduct such operations. 

"The North-South relations are a matter of absolutely our own people, and nobody has any right to meddle with whatsoever," Kwon said. 

Pyongyang is disappointed at and angry about the successive betrayals and provocations by Washington and Seoul over the past two years, he stressed. 

Relations between the DPRK and the ROK warmed up in 2018 with three summits between their leaders Kim Jong Un and Moon Jae-in and the signing of the Panmunjom Declaration.  

But their cooperation stalled after a summit between the DPRK leader and U.S. President Donald Trump collapsed in Vietnam's Hanoi in February last year due to differences over denuclearization and sanctions relief. 

(With input from Reuters)