STOCKHOLM (AFP) - North Korea and Japan wrapped up three days of talks in Stockholm on Wednesday, agreeing to continue their dialogue on Japanese nationals abducted decades ago by Pyongyang.

The meeting at a hotel in the Swedish capital, which saw the exchange of "tough words" at times, came after the two countries held their first official talks in 16 months in Beijing in March.

"Japan and North Korea agreed to continue consultation but there was no concrete agreement as to when and where the two sides will meet," Japanese chief negotiator Junichi Ihara told reporters after Wednesday's one-hour meeting.

"The Japanese side brought up various issues concerning Japanese, including the abduction issue and had serious discussions with North Korea," he said.

"The North Korean side was not refusing to discuss the abduction issue. Its attitude was the same as in the Beijing meeting." He declined to say if there had been actual progress on the abductees in his talks with North Korea's chief negotiator Song Il Ho, the ambassador for talks to normalise relations with Japan.

"We had a serious and frank exchange of views throughout the meeting. At times, tough words were exchanged," Mr Ihara added, but did not elaborate.

The issue of Japanese nationals kidnapped by North Korea to teach at its spy schools is hugely emotional in Japan, and a government that can bring about a solution would earn huge political benefit.

"It's a highly politicised issue in Japan," senior researcher at the Swedish Institute of International Affairs Linus Hagstroem said. "It's an extremely central matter, even affecting how the Japanese people define themselves, the Japanese collective identity."

North Korea outraged Japan when it admitted more than a decade ago that it had kidnapped 13 Japanese in the 1970s and 1980s to train its spies in Japanese language and customs. Five of the abductees were allowed to return to Japan but Pyongyang has insisted, without producing solid evidence, that the eight others are dead.

According to Mr Hagstroem, the process is likely to get stuck at this same stage.

"There have been similar processes in the past which didn't lead to any significant progress, so I'm quite pessimistic," he said.

"The North Koreans can probably not provide a detailed explanation of what happened to some of these people, so it's necessary that the Japanese make some kind of concession, but they are apparently unable to compromise given that the issue is so loaded." The agenda in Stockholm also included North Korea's nuclear and missile programmes, although observers had not expected any significant development in this area. "We also asked North Korea to restrain itself on any action, such as nuclear and missile development, which would heighten tension on the Korean peninsula," Mr Ihara said.