TOKYO (Reuters) - Japan’s top government spokesman left the door open on Wednesday to a possible summit between Prime Minister Shinzo Abe and North Korean leader Kim Jong Un to discuss the matter of Japanese citizens kidnapped by Pyongyang’s agents decades ago.

FILE PHOTO: North Korea's leader Kim Jong Un speaks during a New Year's Day speech in this photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on January 1, 2018. KCNA/via REUTERS/File Photo

Abe, who has made the abductees issue a keystone of his political career, will meet U.S. President Donald Trump next month in Washington ahead of a proposed summit between the U.S. leader and Pyongyang’s Kim, which would follow a planned April meeting between Kim and South Korean President Moon Jae-in.

Worries have surfaced in Tokyo that Japan’s interests, including the abductees’ fate, may be sidelined by recent moves to resolve the crisis over North Korea’s nuclear and missile programs.

“It is important to harmonize policies closely among Japan, the United States and South Korea ahead of the North-South summit and the U.S-North Korea summit,” Chief Cabinet Secretary Yoshihide Suga told a regular news conference.

“After that, while liaising closing among the three countries, we will address how to comprehensively resolve the nuclear, missile and abduction issues. Amid that, we want to consider what would be most effective and address the issues from that perspective,” Suga added.

On Tuesday, a government source said the administration was considering seeking an Abe-Kim meeting. He declined to be identified because he’s not authorized to speak to media.

Abe, 63, has said he would not rest until all 13 of the people North Korea admitted to kidnapping have returned and divulges information about the others that Japan suspects were taken to train as North Korean spies.

But progress has largely stalled since 2002, when five of the 13 returned home. Pyongyang said the other eight were dead.

A ruling coalition lawmaker said that it was too early to plan for two-way talks with Pyongyang on the kidnappings.

“The order is a North-South summit, followed by a U.S.-North Korea summit. We have to see how they go first,” said the lawmaker, who is well-versed in diplomatic affairs.

Speculation about a Abe-Kim summit emerges periodically, especially when his ratings are soggy.

Then-premier Junichiro Koizumi, got a popularity boost after his 2002 visit to Pyongyang and in 2004 when he brought back five children of abductees.

Abe is facing perhaps the worst crisis since taking office as doubts swirl over a suspected cronyism scandal centered on the discounted sale of state-owned land to a school with ties to his wife. He has denied wrongdoing either by himself or his spouse.

(Corrects spelling of North Korean leader’s second name to Jong, in headline and paragraph one.)