Kim Soo-nam vowed on Wednesday to take stern actions against violent protesters as he was sworn in as the country's new prosecution chief.

"(We should) break the vicious cycle by thoroughly investigating not only the violent protesters but also those who instigate and protect them," the prosecutor general said in his inauguration ceremony at the Supreme Prosecutors' Office in southern Seoul.

The remarks were made ahead of a massive rally planned for this coming weekend, after an association of liberal civic groups vowed to go ahead with it in central Seoul on Dec. 5, despite a prohibition order from the police.

Earlier in November, tens of thousands of demonstrators took to the streets in downtown Seoul to protest the government's decision to adopt state history textbooks and reform the labor market. The rally later turned violent as some protesters brandished metal pipes and police fired water cannons at them. (Yonhap)