BEIJING/SINGAPORE -- A senior North Korean official arrived in Beijing on Monday, apparently on his way to Singapore for a summit preparatory meeting with the United States, diplomatic sources here said.

Kim Chang-son, de facto chief of staff to North Korean leader Kim Jong-un, is leading the country's delegation to discuss the logistics and security issues for his upcoming summit with US President Donald Trump, which is expected to be held in the city-state on June 12, according to the sources.

The North Korean officials are expected to take a Singapore-bound flight late in the afternoon.

A US delegation led by Joe Hagin, White House deputy chief of staff for operations, is reportedly set to arrive in Singapore via Japan. The two sides are expected to meet as early as Tuesday, a source said.

On Saturday, Kim Chang-son was spotted taking a flight to Pyongyang at a Beijing airport. Some speculate that he might have cut short a trip to Singapore after Trump abruptly canceled the summit on Thursday.

Pyongyang later expressed a willingness to talk to the US anytime, and Trump recently hinted that the summit could take place as originally planned.

Other officials from the two countries also met to discuss the summit agenda at the truce village of Panmunjom on the inter-Korean border to prepare for the summit.

Sung Kim, who served as US ambassador to Seoul and a top nuclear negotiator, is holding preparatory talks with North Korean counterparts on the northern side of Panmunjom. The talks are said to be underway until Tuesday.

Should the discussions proceed well, Kim Yong-chol, a vice central committee chairman of the North's ruling Workers' Party, could meet US Secretary of State Mike Pompeo for final coordination, possibly in Washington, observers said. (Yonhap)