Kim Jong Un warned the United States on Monday he had a “nuclear button” on his desk ready for use if North Korea was threatened, but offered an olive branch to South Korea, saying he was “open to dialogue” with Seoul.

After a year dominated by fiery rhetoric and escalating tensions over Pyongyang’s nuclear weapons programme, the North Korean leader used his televised New Year’s Day speech to declare his country “a peace-loving and responsible nuclear power” and call for lower military tensions and improved ties with the South. “When it comes to North-South relations, we should lower the military tensions on the Korean Peninsula to create a peaceful environment,” Kim said. “Both the North and the South should make efforts.”

Kim said he would consider sending a delegation to the Winter Olympics Games in Pyeongchang, South Korea, in February. “North Korea’s participation in the Winter Games will be a good opportunity to showcase the national pride and we wish the Games will be a success. Officials from the two Koreas may urgently meet to discuss the possibility,” Kim said.

South Korea said it welcomed Kim’s offer. But U.S.-based experts saw Kim’s speech as a clear attempt to divide Seoul from its main ally, Washington, which has led an international campaign to pressure North Korea through sanctions to give up weapons programs aimed at developing nuclear missiles capable of hitting the United States.

“We have always stated our willingness to talk with North Korea anytime and anywhere if that would help restore inter-Korean relations and lead to peace on the Korean Peninsula,” a spokesman for the South Korean presidency said. Lee Hee-beom, president of the Pyeongchang Organizing Committee, said it welcomed North Korean participation and would “discuss relevant matters with the South Korean government as well as the International Olympic Committee.”