North Korea's planned destruction on Friday of a cooling tower at a nuclear reactor and its submission of a key declaration on its nuclear programme on Thursday held "great symbolic significance," a Chinese government expert said.
"This is a pivotal step on the process of the denuclearization of the Korean Peninsula, which makes a sound atmosphere for the further talks," said Zhang Liangui from the Central Party School of China's ruling Communist Party, the dpa reported.
"The cooling tower has been out of function since the disablement of the Yongbyon [reactor] last year," the government's official Xinhua news agency quoted Zhang as saying.
"But its destruction holds great symbolic significance," he said.
The two moves reflected North Korea's "determination" to denuclearize and would "rebuild the international society's confidence" that six-nation negotiations would finally lead to the end of the nuclear programme, Zhang was quoted as saying.
Television crews from the other five nations - the United States, China, South Korea, Japan and Russia - are already in Pyongyang to film the destruction of the Yongbyon cooling tower on Friday afternoon, the agency said.
Sung Kim, the US State Department's top official on Korean affairs, would also travel to Pyongyang to witness the blowing up of the tower, it quoted an unidentified South Korean official as saying.
But the agency quoted Zhang and other experts as saying that the normalization of relations between Washington and Pyongyang "still had a long way to go" and that the six-party process could yet "face many obstacles."
Qi Baoliang of the China Institute of Contemporary International Relations told the agency that a flurry of diplomatic contacts between the United States and North Korea had helped bring about Thursday's declaration.
The agency said ties were also softened by the visit to Pyongyang in February by the New York Philharmonic, the highest-level cultural exchange since the 1950-53 Korean War.
Current US-North Korean relations were "the best in decades", Qi said.