Families of Japanese nationals abducted by North Korea decades ago said Friday they were shocked by the fatal shooting of former Prime Minister Shinzo Abe, who had long vowed to make resolution of the abduction issue his "life's work."

The former premier "offered help to us from the time our parents' generation was suffering and reached out to the international community" to try to resolve the issue, said 53-year-old Takuya Yokota, head of a group representing the victims' families, in a phone interview.

"I am really sorry and sad and am at a loss for words," said Yokota, a younger brother of abductee Megumi Yokota who was kidnapped at age 13 in 1977.

Takuya Yokota (R) and Tsutomu Nishioka meet the press in Tokyo on July 8, 2022, after the death of former Prime Minister Shinzo Abe, who was shot during a stump speech in Nara for the July 10 House of Councillors election. (Kyodo)

His mother Sakie Yokota, 86, called Abe's death "extremely regrettable" and described him as someone who made "a great effort to get other countries to cooperate on the abduction issue which he long said he wanted resolved."

Abe had addressed the issue of Japanese nationals abducted by North Korea in the 1970s and 1980s as a key political goal during his tenure.

In September 2002, Abe accompanied then Prime Minister Junichiro Koizumi to North Korea as a deputy chief Cabinet secretary and asked him to take a hard-line stance toward Pyongyang, which is said to have helped draw words of apology for the abductions from the nation's then-leader Kim Jong Il.

"When I saw the breaking news, I was just appalled and speechless," 63-year-old Hitomi Soga, one of five abductees repatriated to Japan in 2002, said in a statement.

"I wanted him to witness and rejoice in the moment when all the abductees returned and embraced their families," she mourned.

Yasushi Chimura and his wife Fukie, both 67, who were also among the group who returned from North Korea, said in a statement issued through the local government in Fukui Prefecture, "He told us only just recently that he will do his utmost toward resolving the abduction issue. It is extremely sad and a shame."

The Japanese government officially lists 17 citizens as having been abducted by North Korea and suspects Pyongyang's involvement in other disappearances of Japanese nationals.

Of the 17, five including Soga were repatriated in 2002 following Koizumi's visit to North Korea. While Japan continues to seek the return of the remaining 12, North Korea maintains that eight have died and the other four never entered the country.

Tsutomu Nishioka, chairman of an abductee advocacy group, said Abe "was both strategic and passionate, and he risked his life as a politician to rescue the victims."

Nishioka said Abe's death is a big loss but he hopes Prime Minister Fumio Kishida will do his best regarding the abduction issue.