Japanese police have raided the offices of a pro-North Korean group in Tokyo in connection with the alleged kidnapping of two children in the 1970s.
Families of Japan's missing have long called for answers
Police moved in on two offices linked to the General Association of Korean Residents in Japan, Chongryon, and the house of a 55-year-old woman.
They suspect the woman played a key role in the abduction of two children aged three and six in 1974.
North Korea has admitted abducting Japanese citizens in the 70s and 80s.
But it says that of the 13 people its agents seized, five have been released and eight are dead.
Tokyo has always suspected more citizens were kidnapped, and has refused full-scale economic assistance or the establishment of diplomatic ties with the North until the issue is resolved.
The Japanese authorities said the raids were part of an investigation into the 1974 abduction of two children born to a Japanese woman and a Korean man.
Police sources said they suspected the 55-year-old woman of helping a North Korean agent - who left Japan in the late 70s - to kidnap the children, Kyodo news agency reports.
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
Three top Chongryon officials are also wanted for questioning over the case, the sources said.
There were angry scenes as police moved in on one of the Chongryon offices, Kyodo news agency reports.
Chongryon staff and supporters clashed with police and one man was reportedly arrested for trying to block the search.
Chongryon described the raid as a "political crackdown" by the Japanese authorities ahead of Prime Minister Shinzo Abe's visit to the US.
Mr Abe, who has always taken a strong line on the issue of abductions, is expected to raise the issue when he meets US President George W Bush later this week.
The two children are not thought to be on the government list of Japanese citizens Tokyo believes were spirited away by the North to train its spies in Japanese language and culture.