With the prosecution set to indict Korean-German professor Song Du-yul by Thursday, hundreds of German activists and scholars are launching a campaign for his release.

The Seoul-based Catholic Human Rights Committee, which is leading a movement on behalf of Song here, said on Tuesday more than 600 figures in Germany and other European nations are calling on President Roh Moo-hyun to release the dissident scholar.

Song, a 59-year-old Muenster University professor, was detained last month on charges of violating the anti-communist National Security Law and maintaining close ties with North Korea.

After returning to Seoul in late September for the first time in 37 years, Song has been intensively questioned about his alleged pro-North Korean activities while staying in Europe, such as his membership in the Politburo of the North's Workers' Party.

Prosecutors had indicated that they plan to indict the scholar today or tomorrow, as he has not been cooperative in the investigations and has maintained his previous stance that he had not been officially elected as a member of the Politburo.

To urge for Song¡¯s release, professors from Muenster University and other sociology and philosophy scholars in Germany recently sent a letter to Roh, requesting he grant leniency to Song in light of his contributions to bringing reconciliation between South and North Korea.

``Punishing him in the name of the National Security Law, which has received much criticism overseas, means that Korean society is not moving forward, but retreating to the past,¡¯¡¯ the letter said.

Advocates of Song in Seoul said they will launch a signature-collecting drive across Europe if Song is indicted, together with Korean students overseas and global civic groups.