Prime Minister Shinzo Abe has spoken over the phone with US President Donald Trump ahead of next week's US-North Korea summit.
They discussed an issue of great importance to Tokyo, Japanese nationals who were abducted by North Korean agents decades ago.
After the talks on Wednesday, Abe told reporters: "We agreed that Japan and the US will work even more closely on all levels to resolve the issue of North Korea's nuclear and missile programs, as well as the issue of the abductions of Japanese nationals. We spent a lot of time discussing the abduction issue."
When Abe met relatives of the abductees this week, he said he would explain to Trump the plan he has for resolving the issue and ask the US president to convey his ideas to Kim.
The relatives say they want all of the abductees to return to Japan as soon as possible.
