Twelve South Korean women who were forced into sexual slavery by Japanese military during World War II have sued the Seoul government over a deal it reached with Tokyo to pay the victims, saying it does not go far enough to establish Japan's responsibility.

The women are seeking $90,000 each from the South Korean government, which they say failed to hold the Japanese government legally responsible when it agreed to the settlement in December, a spokesman from the Seoul Central District Court said on Wednesday.

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The lawsuit was submitted days after South Korea's Foreign Ministry said the surviving victims will each be eligible to receive around $90,000 from a foundation funded by the Japanese government.

The ministry said families of deceased victims will receive about $18,000 and added it expects the Japanese government to soon transfer a promised $9.9m to the Seoul-based foundation that was launched in July.

Many in South Korea believe the Seoul government settled for far less and that Japan still has not acknowledged legal responsibility for atrocities during its colonial occupation of the Korean Peninsula from 1910 to 1945.

Several South Korean victims, including at least six of the women who sued the South Korean government, said they will reject payments offered from the foundation.

Under the December agreement, described by both governments as "irreversible", Japan pledged to fund the foundation to help support the victims.

However, it added that it did not consider the promised fund as compensation, saying such issues were settled in a 1965 treaty that restored diplomatic ties and was accompanied by more than $800m in economic aid and loans from Tokyo to Seoul.

South Korea, in exchange, vowed to refrain from criticising Japan over the issue and will try to resolve a Japanese grievance over a statue of a girl representing victims of sexual slavery that sits in front of the Japanese Embassy in downtown Seoul.

Historians say tens of thousands of women from around Asia, many of them Korean, were sent to frontline military brothels, where they were dubbed "comfort women", and used by Japanese soldiers for sex.

At the time of the sex-slave deal, Seoul said there were 46 surviving South Korean victims.

Source: Agencies