Police raided the offices of labor groups on Saturday as part of their ongoing probe into last week's large-scale anti-government rally in downtown Seoul, officers said.

Officers at the Seoul Metropolitan Police Agency raided 12 offices of eight labor unions, including the Korean Confederation of Trade Unions (KCTU), and secured data on the massive protest at the Gwanghwamun Plaza last Saturday.

Some 130,000 demonstrators from 53 labor unions and civic organizations took to the streets against the government's moves to adopt state history textbooks and its drive for labor reforms. As the rally continued late into the night, it turned more violent with protesters brandishing metal pipes and police firing water cannons at the protesters.

According to the authorities, the labor unions have led the violent rallies by attacking police officers with banned tools such as iron pipes and disrupting the exercise of due authorities while illegally occupying streets.

"The groups are suspected of leading the illegal, violent protest, and we will secure evidence to find those who orchestrated them," an officer said, vowing to bring those responsible to justice.

Police also said they have sought to secure data on the KTCU head, Han Sang-gyun, who has taken shelter at the Jogye Temple in central Seoul to avoid the arrest. (Yonhap)