The Hong Kong Federation of Trade Unions is urging local government to ban masks at protests and invoke the Emergency Regulations Ordinance to stop escalating violence and chaos in Hong Kong.

Members of the federation such as Michael Luk Chung-hung and other Hong Kong residents raised a banner which read "calling for the anti-mask legislation to stop violence and return to rationality" and shouted similar slogans outside the government headquarters of the Hong Kong Special Administration Region (HKSAR) Thursday.

In recent months, protesters have rushed police lines, thrown dangerous objects at officers, escalated attacks with deadly weapons, and even have started fires, endangering nearby residents, police and protesters themselves, Luk said.

In order to avoid punishment, protesters often hide their identities by wearing masks, presenting difficulties for police investigating evidence for prosecutors, hindering  law enforcement, and deteriorating social peace, Luk noted.

"The mask ban has been applied in Germany, Austria and Russia, as well as some US states. Many countries and regions will put violators in jail while some countries will fine the masked protesters," Luk said.

The HKSAR government can look to the legal precedent of foreign countries as a  reference for banning masked people in some situations. This can help restrain extremists' illegal actions and protect public security, Luk said.

The union also said that the HKSAR government can invoke the Emergency Regulations Ordinance to deal with the chaos as citizens' lives and property are increasingly threatened.

Hong Kong society needs to stop violence and chaos, so the government should consider any legal measure to help prevent the expansion and escalation of violence, the union said.