TOKYO - After years of wrangling with North Korea, Japan is appealing to the international community to help bring back Japanese citizens abducted several decades ago by North Korea.

Pyongyang agreed two years ago to reopen an investigation into the abductions of 12 people kidnapped to train North Korean spies. But Japan has been frustrated by Pyongyang's refusal to return or adequately explain what happened to the abductees, an issue that has bedeviled relations between the two countries for years. After stalling for a year, North Korea angrily declared in February that it was stopping its investigation.

Katsunobu Kato, Japan's minister in charge of the abduction issue, will deliver an address in Washington this week and then at the U.N. to ask the international community to help "extract and induce" cooperation from North Korea's leader, Kim Jong Un.

"Our position is to strongly demand that the judgment is made [to resume discussions]," Kato said in an interview in his office, adorned with posters of the most famous abductee, Megumi Yokota, a 13-year-old who was taken on her way home from school in 1977.

During the 1970s and early 1980s, North Korea operated a state-sponsored abduction program in which it snatched young Japanese and put them on a boat to North Korea, where they were used to train spies to speak their language and pass for Japanese.

In a surprise development, North Korea admitted in 2002 that it had been abducting Japanese and agreed to return five of the people on Japan's list of 17. But it said that eight of the others on the list, including Megumi, had died in North Korea and that the other four never entered the country.

The issue was dormant until an agreement in 2014 in which Tokyo agreed to ease sanctions on North Korea and Pyongyang agreed to investigate what had happened to the abductees.

But Pyongyang never submitted the reports it promised or made further progress and the negotiations stalled. Then, after this year's nuclear and missile tests, Japan reinstated old sanctions and imposed new ones on North Korea, and supported multilateral measures.

In response, North Korea's investigation committee said its work "will be totally stopped."