Japanese negotiators have begun new talks in North Korea on the fate of Japanese nationals allegedly abducted by Pyongyang in the 1970s and 80s.
Relatives of the missing are putting pressure on Tokyo to find answers
The two sides sat down together on Wednesday, in talks set to last three days.
Officials from the two countries have already met twice this year to discuss the issue, but failed to make progress.
Senior members of Japan's ruling party are calling for economic sanctions if this round of talks is unfruitful.
Pyongyang allowed five abductees to return to Japan in 2002, but claims other missing Japanese are now dead.
The BBC's Tokyo correspondent, Jonathan Head, says there is strong public pressure on the Japanese government not to improve ties with North Korea until it gives a full account of what happened to all the Japanese abductees.
"If North Korea does not show a sincere attitude, we should not go along with their stalling tactics," Shinzo Abe, deputy secretary general of the ruling Liberal Democratic Party, told a seminar in Tokyo.
Snatched in the '70s and '80s
Used as cultural trainers for N Korean spies
Five allowed home in 2002
Five children now freed from N Korea
Eight said to be dead, others missing
"While watching the situation, I would like to urge the government to impose economic sanctions," he said.
North Korea admits having kidnapped 13 people in all, who were used to train Korean spies. Five have returned to Japan, and Pyongyang says the rest have died.
But Tokyo is sceptical, and wants proof the others are dead. It also wants information on another two people whom North Korea says never entered the country.
North Korean leader Kim Jong-il pledged in May to reinvestigate the cases.
The Japanese delegation is expected to meet the husband of one of the Japanese North Korea says has died - Megumi Yokota - along with the doctor who wrote her medical records.
The abduction is a major stumbling block to the establishment of diplomatic ties, which would win Pyongyang substantial economic aid from Japan.
The Japanese delegates are also due to urge North Korea to restart multinational talks on its nuclear weapons programme.
The last round of talks scheduled for September never took place and it was widely speculated that Pyongyang was waiting to see who won the US elections.
North Korea has blamed the Bush administration's "hostile policy" for the nuclear stand-off.