Pyongyang also accused the South Korean leader of “escalating confrontation with the fellow countrymen through strengthened cooperation with the foreign forces in the anti-DPRK sanction and pressure racket”.
Mr Moon spent four days in China for talks with Xi Jinping.
The pair agreed to four principals for handling North Korea and resolving the rapidly escalating nuclear tension.
The comments come as Pyongyang has vowed to become the “world’s most powerful nuclear and military state” as UN sanctions and threats from Donald Trump do nothing to stop the efforts of Kim Jong-un.
The hermit state has announced it is hurtling towards a fully fledged nuclear weapons programme and will not be stopped by China imposing sanctions which are strangling the nation’s economy.
Referencing the “two fronts” plan, the representative said the North’s blueprint for success lies in nuclear power and a strong economy.
He said: “(Pyongyang) Will march forward and make great advancement victoriously as world’s most powerful nuclear and military state upholding the line on simultaneous development of the Two Fronts.”