But North Korea refused, protesting that Tokyo had already broken its promise to send back the visiting Japanese nationals, Japanese government sources said.

The row over the kidnappings comes amid heightened tension over North Korea's nuclear ambitions, following its alleged admission to having a nuclear weapons programme.

Pyongyang has said it will only discuss the nuclear issue with the US, as part of a non-aggression pact.

Time running out

Tokyo said it would now be difficult to resolve the abduction issue with North Korea before talks are due to restart at the end of November.

"Under the current situation, I feel it's become difficult because of a time shortage," Japanese Chief Cabinet Secretary Yasuo Fukuda said at a news conference.

"There are still differences between both sides... over how to go ahead with the talks. Unfortunately, we are also divided over the abduction issue," he said.

Five Japanese nationals, kidnapped by North Korea in 1978, returned home for the first time in 24 years in mid-October.

They were only supposed to stay for around a fortnight, but Japan has refused to return them to an uncertain fate in North Korea.

However, the five visitors are anxious about their families who remain in the Stalinist state.

North Korea has argued that such issues can only be resolved once ties between the two sides are normalised. Japan wants the issues resolved first.

Tokyo intends to discuss setting a new date for talks in early December with Pyongyang, the Mainichi newspaper reported.

"We'll patiently negotiate with North Korea in order to resume the talks within this year," Japanese Prime Minister Junichiro Koizumi was quoted as saying by the paper.

Nuclear concerns

North Korea has also indefinitely postponed security talks which the two sides had agreed to hold by the end of this month, the paper said.

Tokyo wants Pyongyang to renounce its nuclear ambitions. North Korea has allegedly admitted to a nuclear programme, and has recently repeatedly threatened to end its moratorium on missile testing.

The US has said it will suspend oil shipments from December to try to force North Korea to abandon the programme.