Diplomacy accelerated on Tuesday ahead of a potential summit between US President Donald Trump and Democratic People's Republic of Korea leader Kim Jong-un, as a senior official of the DPRK prepares to travel to the United States for working-level talks.

Citing an unidentified source, the Republic of Korea's Yonhap News Agency reported that Kim Yong-chol, vice-chairman of the Central Committee of the Workers' Party of Korea, will fly to the US on Wednesday for talks with Secretary of State Mike Pompeo on a possible summit between Kim and Trump. Kim Yong-chol's visit would make him the highest-ranking DPRK official to step onto US soil since late National Defense Commission First Vice-Chairman Jo Myong-rok visited Washington in 2000.

Trump canceled the planned June 12 summit in Singapore on Thursday, citing Pyongyang's recent "open hostility". However, he reversed course the next day, saying the summit could still go ahead after productive talks.

Trump on Sunday confirmed that a US official team had traveled to the DPRK to prepare for the summit. Sung Kim, Washington's ambassador to the Philippines, headed the team on Sunday and met with Choe Son-hui, DPRK's Vice-Foreign Minister in the truce village of Panmunjom.

The two sides were reported to have discussed denuclearization methods and timelines as well as ways to ensure the DPRK's security, Yonhap reported.

The talks are running in concert with both the US and the DPRK sending envoys to Singapore.

A group of US government officials, including Joe Hagin, the White House deputy chief of staff for operations, left US Yokota Air Base in Japan for Singapore on Monday to arrange logistical preparations for the summit, according to Japan's public broadcaster NHK. The media also reported that Kim Chang-son, Kim Jong-un's de facto chief of staff, flew to Singapore via Beijing on Monday night. A Xinhua report on Tuesday confirmed Kim Chang-son was in Singapore.

An unnamed diplomatic source was cited in the report, which said the two sides were scheduled to meet in Singapore on Tuesday and hold consultations over such practical issues as a firm summit date, the venue, protocol and security.

Expectations are running high that the Kim-Trump summit will still be held as scheduled, yet Pyongyang urged the US on Tuesday to stop its large-scale joint military exercises with the ROK to create a favorable atmosphere for dialogue.

Xinhua contributed to this story.