The intelligence chiefs of South Korea, the United States and Japan were to hold a closed-door trilateral meeting in Seoul on Tuesday to discuss North Korea and other pending issues, a government source said.

Park Jie-won, the head of South Korea's National Intelligence Service (NIS), was set to sit down with Avril Haines, the US director of national intelligence, and Hiroaki Takizawa, Japan's Cabinet intelligence director, according to the source.

During the talks, the top intel officials are expected to share their assessments of the security situation on the Korean Peninsula, including President Moon Jae-in's recent proposal to declare a formal end to the 1950-53 Korean War.

The three last held such a meeting in May in Tokyo.

Tuesday's meeting follows Park's bilateral talks with his US and Japanese counterparts, and Haines' meeting with Suh Hoon, director of national security at Cheong Wa Dae, the previous day.

Also high on the agenda is Tokyo's new policy direction on North Korea, as Takizawa's Seoul visit is his first since Japan's new Prime Minister Fumio Kishida took office earlier this month.

The meeting comes amid a flurry of diplomatic activities to revive the long-stalled denuclearization talks between Washington and Pyongyang, with the North test-firing four new missiles last month.

In Washington, top nuclear envoys of South Korea, the US and Japan gathered for talks, during which US Special Representative for North Korea Policy Sung Kim said Washington harbors "no hostile intent" toward the North and that it was "prepared to work cooperatively with" Pyongyang on humanitarian concerns.

Kim is set to visit Seoul later this week to continue discussions on North Korea. (Yonhap)