North Korea on Monday accused the United States of "political and military provocations" and South Korea of "double-dealing behavior."
North Korea's UN Ambassador Kim Song made the accusations in a speech to a General Assembly meeting on the International Atomic Energy Agency, which he accused of "ignorance of the prevailing reality of the Korean peninsula."
Kim said relations between the US and North Korea "have made little progress" since the June 2018 summit between their leaders, "and the situation of the Korean peninsula has not extricated itself from the vicious cycle of aggravated tension."
He said this is "entirely attributable to the political and military provocations perpetrated by the US"
Since the start of nuclear talks last year, the US and South Korea have cancelled or scaled back regular military drills to create space for diplomacy. But North Korea sees any drills as a rehearsal for an invasion.
Nuclear diplomacy has largely remained deadlock since a second summit between US President Donald Trump and North Korean leader Kim Jong Un failed in February.
In recent months, North Korea has been trying to pressure the United States after demanding that Washington make new proposals to revive nuclear diplomacy by the end of December.
Kim, the North Korean UN envoy, told the 193-member General Assembly that since last year his country his country has made "proactive efforts in good faith ... to establish a lasting peace regime on the Korean peninsula."
He said North Korea has refrained from testing nuclear weapons and intercontinental ballistic missiles for more than 20 months.
Kim said "the key" to consolidating peace and security is implementation of the joint statement the leaders adopted at last year's Singapore summit.
As for inter-Korean relations, the North Korean envoy said they are now at a "standstill, without even advancing into the main phase of implementation."
He said this is "attributable to the double-dealing behavior of the South Korean authorities," which he described as appearing to offer peace initiatives while escalating military preparedness.
Acting IAEA Director General Cornel Feruta told the assembly that it has been more than 10 years since the agency's inspectors were ordered to leave North Korea, which is also known by its official name, the Democratic People's Republic of Korea.
But he said "the agency continues to monitor the DPRK's nuclear program, including through satellite imagery."
Feruta said North Korea's nuclear activities "remain a cause for serious concern" and clearly violate UN Security Council resolutions.
He called on North Korea to comply with its UN obligations and "cooperate promptly" with the IAEA.
