North Korea's sudden change in attitude was probably driven by the mounting global sanctions imposed over its weapons programmes that had begun to take a toll on the livelihoods of ordinary citizens, Thae said.
"North Korea's diplomacy has always been a repeat of hardline and appeasement", Thae said.
North Korea's Foreign Ministry announced Saturday that it will dismantle the test site between May 23 and 25.
On Monday, a person who appeared to be a high-ranking North Korean official arrived in Beijing and was staying at the Diaoyutai State Guesthouse, where foreign dignitaries usually are accommodated on visits to China's capital, according to a source close to the matter. Thae predicts it would then eventually seek joint economic projects with South Korea, such as the Kaesong Industrial Complex that used to employ North Korean civilians and provided a revenue stream for the regime. "Clearly, the ballistic missiles program, as with Iran, with the intention of being a delivery system for nuclear weapons - that's gotta go".
Lisa Collins, a fellow with the Korea Chair at the Center for Strategic & International Studies, said it is still too early to tell what will be accomplished in the first meeting between Trump and Kim. They also agreed to stop all hostile acts over "land, sea and air" that can cause military tensions and clashes, establish a liaison office in the North Korean border town of Kaesong, and to resume temporary reunions between war-separated families.
Top leader of the Democratic People's Republic of Korea (DPRK), Kim Jong-un shakes hands with US Secretary of State Mike Pompeo in this May 9, 2018 photo released on May 10, 2018 by North Korea's Korean Central News Agency (KCNA) in Pyongyang.
But Beijing is keen to avoid being sidelined in the wake of Kim's historic summit last month with South Korean President Moon Jae-in and ahead of his upcoming meeting with Trump in Singapore on June 12.
But there are lingering doubts on whether Kim will ever agree to fully relinquish his nukes. Pyongyang for decades has been pushing a concept of "denuclearization" that bears no resemblance to the American definition, vowing to pursue nuclear development unless Washington removes its 28,500 troops from South Korea and the nuclear umbrella defending South Korea and Japan.