A group of South Koreans claiming they were sex slaves or forced laborers before and during World War II filed an appeal Thursday with the Supreme Court in a bid to overturn a high court decision last month rejecting their compensation demands, their lawyers said.

On March 29, the Hiroshima High Court overturned a landmark 1998 district court ruling ordering the Japanese government to compensate South Korean former "comfort women" forced to provide sex for Imperial Japanese Army soldiers.

"At this moment, we cannot disclose the reasons why we are filing this appeal, but we believe it will shed light on how unconstitutional (the high court ruling) was," said Lee Pak Song, a lawyer representing the plaintiffs.

While the district court said the government has failed to provide laws to compensate the women, the high court said in overturning the ruling that issues of compensation for wartime suffering are a matter for the Diet and not the judiciary.