North Korea’s UN envoy has said that Pyongyang will accelerate a buildup of its nuclear weapons programme just days after it test-fired an intercontinental ballistic missile for the first time this year at a moment of rising tensions with the west. Kim Song, North Korea’s ambassador to the UN, said during a security council meeting on Monday that Pyongyang would accelerate the programme to “counter any threat presented by hostile nuclear weapons states”. The security council meeting was convened to address Pyongyang’s testing of an intercontinental ballistic missile on Thursday meant to demonstrate North Korea’s growing prowess at developing missiles that could deliver more powerful nuclear warheads potentially to the mainland US. The US and Ukraine have warned that North Korea has nearly 8,000 soldiers stationed in the Kursk region of Russia who could go into combat in Ukraine in the coming days, and both countries have warned that those troops will become legitimate military targets if they take part in fighting. “The nuclear threat of United States against [North Korea] has already reached critical point in terms of its scale and danger,” Kim said. “Due to reckless moves of the United States, the potential situation is approaching the brink of war.” During the meeting, the US accused China and Russia of “shamelessly” protecting Pyongyang at the UN from “closer scrutiny of its sanctions-violating activities”, and said Pyongyang had been “emboldened to continue advancing its unlawful ballistic missile, nuclear and WMD programmes”. North Korea is believed to be seeking Russian missile and space technology as part of a deal to provide troops in Russia’s war against Ukraine. But US officials have not said what they believe Vladimir Putin has provided to North Korea in exchange. “Russia and China have shamelessly protected Pyongyang from any reprisal, or even condemnation of its actions,” said Robert Wood, the deputy US ambassador to the UN. Vladimir Putin greeted North Korea’s foreign minister in a surprise meeting in the Kremlin after the US warnings about North Korean soldiers approaching Ukraine. Footage was broadcast showing Putin meeting Choe Son Hui, the North Korean envoy, with whom he shook hands for a full minute. The meeting took place on Russia’s National Unity Day, a national holiday, and Choe said he brought “sincere, warm, comradely greetings” from the North Korean leader, Kim Jong-un. The meeting was not previously scheduled and may have been prompted by the warnings by the west about the North Korean troops preparing to fight. The US and South Korea announced a new memorandum of understanding to develop cooperation on civil nuclear energy, strengthening their “administration of export controls on civil nuclear technology”, the US Department of Energy said in a statement. The department claimed that the announcement would help combat the climate crisis and protect critical supply chains, while “creating billions of dollars worth of new economic opportunities”.