Share Saul Loeb/AFP/Getty ImagesA photo from North Korea’s official Korean Central News Agency (KCNA) taken and released on January 1 showing North Korean leader Kim Jong-Un delivering a New Year’s speech and President Trump speaking during a cabinet Meeting on Dec. 20.Updated at 1:55 a.m. ETPresident Trump and North Korean leader Kim Jong Un are once again publicly comparing the size of their respective nuclear arsenals, with the president tweeting that the U.S. “nuclear button” is “much bigger & more powerful” than the one controlled by Pyongyang.Trump’s comment on Twitter comes in response to Kim’s New Year’s address in which the Korean leader warned that the whole of U.S. territory is “within the range of our nuclear strike.”North Korean Leader Kim Jong Un just stated that the “Nuclear Button is on his desk at all times.” Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!— Donald J. Trump (@realDonaldTrump) January 3, 2018Mocking Kim, the president wrote: “Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!”AFP/AFP/Getty ImagesSouth Korean Lieutenant Choi Don-Rim, left, communicates via a hotline with a North Korean officer at a military office near the Demilitarized Zone (DMZ) in 2005The remark comes on the same day that Pyongyang announced that it would re-establish a long-closed border hotline. On Wednesday, South Korea said it had already established “preliminary contact” over the line at the truce village of Panmunjom. In response, Seoul offered Jan. 9 talks with the North to discuss cooperation at the Winter Olympics next month in PyeongChang, South Korea. Pyongyang has yet to respond.Sanctions and “other” pressures are beginning to have a big impact on North Korea. Soldiers are dangerously fleeing to South Korea. Rocket man now wants to talk to South Korea for first time. Perhaps that is good news, perhaps not – we will see!— Donald J. Trump (@realDonaldTrump) January 2, 2018NPR’s Rob Schmitz reports that “South Korean officials are calling the announcement a very significant step” but he cautions “[there] have been repeated attempts in recent years by the rivals to talk, and even when they do meet, the efforts often end in stalemate.”Earlier on Tuesday, the president referred again to Kim as “Rocket man” and implied that U.S.-led sanctions against Pyongyang had caused the North Korean regime to open dialogue with Seoul.However, U.S. Ambassador to the United Nations, Nikki Haley, speaking to reporters, appeared to pour cold water on the prospect of substantive change in relations on the Korean peninsula.“We won’t take any of the talks seriously if they don’t do something to ban all nuclear weapons in North Korea,” Haley said at the United Nations. “We consider this to be a very reckless regime. We don’t think we need a Band-Aid, and we don’t think we need to smile and take a picture.”Since the start of the New Year, Trump has tweeted at least 19 times, lashing out not only at North Korea, but Pakistan, Iran, and the Palestinians, in addition to “Crooked Hillary Clinton,” Democratic lawmakers in Congress and “the Fake News Media.”Copyright 2018 NPR. To see more, visit http://www.npr.org/.