In response to Pyongyang's implied threat to halt bilateral negotiations, Tokyo will strongly urge the reclusive country to proceed on the promised re-investigation into the whereabouts of the Japanese nationals it abducted, Japanese sources said.
Pyongyang protested through diplomatic channels the police raid on the home of the head of the General Association of Korean Residents in Japan (Chongryon) late last month and said the negotiations "are facing difficulties."
Japan plans to use diplomatic channels to express its intolerance of the North's stance. It may also step up economic sanctions against the country, the sources said.