The families of two of the 11 Japanese nationals allegedly abducted by North Korean agents demanded Wednesday that Prime Minister Junichiro Koizumi push hard to resolve the issue at next week's summit in Pyongyang.

Speaking at a Tokyo news conference, Shigeru and Sakie Yokota and Teruaki Masumoto said Koizumi should remember the statement he made in March: "Without the resolution of the abduction issue, there can be no normalization of diplomatic ties."

The Yokotas' daughter, Megumi, disappeared in Niigata Prefecture in 1977 at age 13. Masumoto's elder sister, Rumiko, went missing at age 24 near the coast of Kagoshima Prefecture in 1978.

"I hope Koizumi will bring back (some of the missing) with him on the plane," said Shigeru Yokota. "But if this is difficult, I hope he will bring home concrete progress on the issue, such as (facts about) their whereabouts or when they will return."

Masumoto said he is worried that Koizumi might put establishing diplomatic relations above the resolution of the adduction issue.

"If he comes back empty-handed (on the abduction issue) and resumes normalization talks, the Japanese public will be disappointed in him, which might result in a political change."

The summit is slated for Tuesday.

Tokyo believes that at least 11 Japanese nationals were abducted by North Korean agents in the 1970s and 1980s. The abduction issue has been a major stumbling block to normalizing diplomatic ties between Japan and North Korea.