North Korea abruptly suspended high-level talks with the South scheduled for last week, citing an ongoing joint military exercise of the two allies. It has also threatened to reconsider the Trump-Kim summit, set to be held in Singapore on June 12. 

"We expect the upcoming South Korea-US summit to play a role as a bridge (between the US and North Korea) that will lead to the success of the North Korea-US summit as it comes three weeks before the North Korea-US summit," Nam Gwan-pyo, a deputy director of the presidential National Security Office, said earlier.

Moon and Trump will likely discuss "ways to guarantee a bright future for the North when North Korea achieves complete denuclearization," he added.

In the Panmunjom Declaration, the leaders of the two divided Koreas agreed to pursue complete denuclearization of the Korean Peninsula.

In a gesture demonstrating its denuclearization commitment, the North is moving to dismantle its only known nuclear test facility in Punggye-ri this week with dozens of journalists from South Korea, China, Russia, Britain and the US witnessing the event.

Still, its recent suspension of inter-Korean dialogue is sending out mixed signals, also forcing many to question the sincerity of its pledge to abandon its nuclear ambitions.

During talks with Trump, Moon is expected to discuss what to expect and what not to expect from Kim based on his own encounter with the North Korean leader last month, officials from Seoul's presidential office Cheong Wa Dae said.

The officials said Moon and Trump are set to hold a one-on-one meeting where they will be accompanied by their interpreters and no one else.

"The fact that the two leaders will hold talks with no other attendants is important. It will likely be a chance for them to share their inner-most thoughts," a Cheong Wa Dae official said, while asking not to be identified.

Moon will head back home Wednesday following his two-day trip to the US He will arrive back here early Thursday. (Yonhap)