Relatives of Japanese abducted by North Korea voiced concern Thursday that the government was rushing into an fruitless agreement with Pyongyang to resolve the long-standing issue.

"We hope the Japanese government will not blindly ingest everything North Korea feeds it. They must conduct thorough checks," Shigeo Iizuka told reporters after being briefed on the accord in Tokyo.

North Korea agreed Wednesday to reopen and complete a probe into its abductions of Japanese by this fall. In return, Tokyo will lift some economic sanctions.

Iizuka represents an association of Japanese whose relatives were abducted by the North in the 1970s and 1980s. His sister, Yaeko Taguchi, was kidnapped in 1978. The only thing Pyongyang has revealed about her is that she died in an auto accident in 1986. Iizuka doesn't believe this.

"North Korea has at times made complete fabrications," Iizuka said, fearing Japan may be fooled into lifting sanctions against the hermit state.

The relatives said Akitaka Saiki, director general of the Foreign Ministry's Asian and Oceanian Affairs Bureau, told them that the discussions worked in Japan's favor. He also said the North was made aware that lack of progress in the probe could ruin already strained bilateral relations.

But despite being told that reciprocation would not be unconditional, the relatives said they were worried Pyongyang might hype partial progress and demand a deal.

"I have the impression that North Korea held the upper hand during the bilateral discussions," said Teruaki Masumoto, whose sister, Rumiko, was abducted in 1978.

He warned that granting unjustified concessions to the North will anger the relatives if their concerns aren't sufficiently addressed.

Afterward, Kyoko Nakayama, state minister in charge of the abduction issue, said, "I think the family members firmly understand that this is not the end of the negotiations."