Prime Mister Hwang Kyo-han on Tuesday vowed to take stern measures against those committing violent acts while hidden behind face masks during street rallies.

"Those committing illegal acts and (taking part in) violence while hiding behind anonymity with face masks should be sternly punished after gathering evidence during rallies," Hwang said during a Cabinet meeting.

The comment came after a massive anti-government rally in downtown Seoul last month led to violent clashes as protesters brandished metal pipes and police fired water cannons at the protesters.

Tens of thousands of labor and civic group activists took to the streets on Nov. 14 against the government's moves to adopt state-authored history textbooks and labor reforms.

President Park Geun-hye also earlier said she will not tolerate "illegal" demonstrations and instructed officials to come up with strong measures to root out violent protests.

She drew a comparison with Islamic State terrorists, saying demonstrators should not be allowed to wear masks.

A group of some 30 Saenuri Party lawmakers, led by National Assembly Vice Speaker Jeong Kab-yoon, also proposed an amendment to the law on assembly and demonstration, banning participants in violent rallies or protests from wearing masks or other apparel that hides their identity.

In 2009, then-ruling party lawmakers proposed revisions to the public assembly to prohibit protesters from wearing masks to cover their faces, arguing that anonymity tends to fuel violence. The bill was not passed at the time. (Yonhap)