North Korea's ambassador to the United Nations on Monday urged the United States to implement last year's agreement between the leaders of the two nations, accusing the U.S. of "political and military provocations."

Ambassador Kim Song made the call during a speech at a UN General Assembly meeting on the International Atomic Energy Agency(IAEA) in New York.

Kim said that since the 2018 summit in Singapore, the two nations have made little progress in their relations and that the situation on the Korean Peninsula has not "extricated itself from the vicious cycle of aggravated tension."

The ambassador then said this is entirely attributable to the political and military provocations perpetrated by the U.S., stressing that the implementation of the Singapore agreement is the key to consolidating peace and security. 

Kim also accused South Korea of duplicity, saying inter-Korean relations have been at a standstill because Seoul appears to offer peace initiatives while escalating military preparedness.

Meanwhile, IAEA acting Director General Cornel Feruta said at the meeting that the North's nuclear activities remain a cause for serious concern and that its nuclear program is a clear violation of UN Security Council resolutions.

While urging North Korea to immediately cooperate with the IAEA, Feruta said that his agency continues to monitor the North's nuclear program, including through satellite imagery.