While the three leaders were holding talks on Wednesday, US Secretary of State, Mike Pompeo, arrived in Pyongyang to meet with North Korean leader Kim Jong Un ahead of the first-ever US-North Korean summit between President Donald Trump and Kim, Japanese broadcaster NHK reported.
"I once again thank you for China's support and cooperation in the process of realizing the South-North Korea summit".
At the start of the 75-minute meeting, Abe said, "Japan, China and South Korea must cooperate with the global community and strongly ask North Korea to take specific action" toward denuclearization, namely abandoning its weapons of mass destruction and ballistic missiles.
Diplomatic relations between the two nations, clouded by Japan's occupation of parts of China before and during World War Two, have gradually improved after deteriorating sharply in 2012, when Tokyo nationalized a cluster of disputed East China Sea islets that China also claims.
The leaders of Japan, China and South Korea held a summit in Tokyo on Wednesday and agreed to cooperate over the denuclearisation of North Korea.
As Prime Minister Shinzo Abe and Chinese Premier Li Keqiang met for the first time in Tokyo, the two countries, whose ties were strained for years over territorial and wartime issues, signed a range of cooperation agreements, covering areas such as investment, infrastructure-building and social security. "We are willing to continue to play a constructive role in the denuclearization of the Korean peninsula".
"We must take the recent momentum towards denuclearization on the Korean peninsula and towards peace and security in Northeast Asia, and, cooperating even further with global society, make sure this is linked to concrete action by North Korea", Abe told a news conference after the meeting.
"Momentum for improvement in the Japan-China relationship, which has kicked off a new start, has been increasing quickly", Abe told a joint news conference. He said that as major traders in the world, the three sides all support free trade and open markets.
Moon assured Abe that no such steps would be taken without conferring with the United Nations, the United States and others.
Li is scheduled to remain in Japan until May 11.
In late March, Kim made a surprise visit to Beijing and held talks with Xi, his first known trip overseas since he assumed power in 2011.