SEOUL, South Korea: South Korean President Moon Jae-in on Monday welcomed North Korea’s announcement that it is set to dismantle its only nuclear test site, calling it a start to the country’s nuclear disarmament. North Korea said Saturday that it will dismantle its northeastern Punggye-ri test site between May 23 and 25 in the presence of local and international media. The dismantling would come before North Korean leader Kim Jong Un and US President Donald Trump meet for June 12 talks in Singapore expected to focus on Kim’s nuclear program. Moon said Monday that the North’s move shows how sincere the country is about making the talks between Kim and Trump a success. “This would be a preliminary step toward complete denuclearization,” Moon said during a meeting with his aides, according to his office. Trump, in a tweet Saturday, already thanked North Korea for its plan to dismantle the nuclear test site, calling it “a very smart and gracious gesture!” After months of tensions over his nuclear and missile tests, Kim has been reaching out to Washington and Seoul since the beginning of the year. He sent a delegation to February’s Winter Olympics in South Korea, held a landmark summit with Moon in April and last week released three Americans detained in North Korea. Kim is also willing to place his nuclear program up for negotiations in return for security assurances, according to Seoul. But some experts still doubt how committed Kim is to taking serious disarmament steps because his country was close to achieving its goal of possessing nuclear missiles targeting the mainland US after decades of struggle. Moon’s office previously said Kim told Moon during their April 27 summit that he would allow not only outside journalists but also experts to watch the dismantling of the Punggy-ri test site. But the North’s announcement Saturday did not mention anything about inviting experts to Punggy-ri, spawning speculation that the North may want to hide some information about its past nuclear tests. Some experts have downplayed the closure of the Punggy-ri site, where all six of the North’s known underground nuclear explosions happened, saying it is already too unstable for more testing. Kim has denied such views, saying the site has two additional underground tunnels that could be used for new tests.