Police were investigating a total of 868 missing persons cases as of Nov. 1, including some in which the possibility the victims were abducted by North Korea cannot be ruled out, members of support groups said.

The information was revealed Friday by the National Police Agency, following a right to know request submitted by a group in Tokushima Prefecture that campaigns on behalf of abduction victims and their families.

It is the first time that the total number of missing persons cases has been publicly disclosed, according to the agency's Foreign Affairs Division.

According to documents released by the NPA on Dec. 6, there were 81 such cases in Hokkaido, the largest number by prefecture, followed by 65 in Osaka, 58 in Tokyo, 46 in Niigata and 45 in Kanagawa. Of the total 868 cases, 636 of the missing are male and 232 are female.

"This is a serious number," Toshiro Suehisa, head of the Tokushima group, said at a news conference, adding his organization is closely following developments to see whether the government will officially acknowledge that any of the victims were abducted by North Korea.

The government recognizes 17 Japanese nationals as having been snatched by Pyongyang's agents in the 1970s and '80s. The North continues to insist that it only abducted or lured 13 Japanese during this period. It further claims that eight of the abductees have since died, an assertion rejected by Tokyo, while the other five victims were repatriated in 2002.

The abduction issue remains a formidable obstacle to normalizing diplomatic ties between Tokyo and Pyongyang, especially as the North maintains the matter has already been fully resolved.