The relatives of Japanese abducted by North Korean agents decades ago expressed hope and concern that Republican Donald Trump's victory in the U.S. presidential election might further jeopardize progress on the issue.

Shigeo Iizuka, 78, head of a group representing abductees' families, said Wednesday that he hopes the president-elect will press North Korea to resolve the abduction issue.

After admitting to the abductions in 2002, he said Pyongyang allowed five abductees, including Kaoru Hasuike, to return to Japan after "strong pressure" from the United States.

Iizuka's younger sister Yaeko Taguchi was kidnapped in 1978 when she was 22.

There has been no substantial progress in talks on the issue, although North Korea agreed with Prime Minister Shinzo Abe's government in 2014 to reinvestigate the abductions.

Pyongyang said in February it was suspending the probe in response to tougher sanctions imposed by Japan over its nuclear and missile tests.

With negotiations between the two countries stalled, "I hope (the Japanese government) will show its firm stance to the United States to solve the issue by any means," Iizuka added.

Japan officially lists 17 nationals as abduction victims but suspects North Korea's involvement in more disappearances. The abduction issue remains an obstacle to normalizing diplomatic ties between the countries.

Kayoko Arimoto, 90, the mother of Keiko Arimoto who was abducted in 1983 at the age of 23, stressed the need for Washington's help in resolving the issue but expressed concern over whether the new president will address it seriously.

"I am worried because Mr. Trump has said things like leaving alone the matters of other countries," she said.