Japanese Prime Minister Shinzo Abe on Tuesday called on North Korea to take concrete steps toward denuclearization after the country's leader Kim Jong Un expressed readiness to hold talks with the United States over the issue.

"It is extremely important for North Korea to take concrete steps and implement what it has said" to realize a nuclear-free Korean Peninsula, Abe said in a meeting with one of the South Korean envoys who met Kim earlier this month in Pyongyang.

During their talks at the prime minister's office, Abe and Suh Hoon, director of South Korea's National Intelligence Service, agreed to firmly work together bilaterally and trilaterally with the United States toward that goal, according to Japan's Foreign Ministry.

Speaking to reporters after the meeting, Suh said Abe "expressed his respect for (South Korean) President Moon Jae In's leadership in improving relations between South and North Korea, and maintaining peace toward denuclearization on the Korean Peninsula."

After Suh and other delegates met Kim in Pyongyang on behalf of the South Korean president, both Moon and U.S. President Donald Trump agreed to hold bilateral summits with the North's leader in the coming months.

The Japanese prime minister also promised cooperation "in all ways possible" for the success of the envisioned inter-Korean and U.S.-North Korean summits, according to the South Korean envoy, who is visiting Tokyo to brief Japanese officials on his Pyongyang trip.

Abe has said he will visit the United States early next month to hold talks with Trump to coordinate their policies on North Korea ahead of what would be the first-ever meeting between a sitting U.S. president and a North Korean leader.

During the meeting with Abe, Suh conveyed Moon's "message that cooperation between South Korea and Japan is necessary to turn peace moves on the Korean Peninsula created by the Pyeongchang Olympics into something positive."

"I believe such a good mood began as Prime Minister Abe and U.S. Vice President (Mike) Pence attended the opening ceremony of the Pyeongchang Olympics," he added.

On Monday, Japanese Foreign Minister Taro Kono and Suh, who visited Washington after Pyongyang, agreed to work in close coordination on the issue of North Korea's abductions of Japanese nationals decades ago.

Japan has expressed its readiness to assist the process of North Korea's denuclearization by covering the initial costs needed for the International Atomic Energy Agency to resume stalled inspections of the North's nuclear facilities.

South Korea's National Security Office chief Chung Eui Yong, who led the delegation to Pyongyang and traveled to Washington with Suh, visited China on Monday to brief President Xi Jinping and other senior officials about the South Korean envoys' meeting with Kim.