Clashes erupted between the state police and protesters, who tried to storm the Legislative Council here on Monday, the 20th anniversary the former British colony's return to China.
Protestors removed metal fencing and smashed glass doors at the Legislative Council building, prompting the Council to issue a "red alert" for the first time in Hong Kong's history, The Washington Times reported.
Videos broadcasted from inside the building by local television networks showed riot police standing behind metal shutters as protesters repeatedly slammed against them and tried to pry them open in an apparent effort to fully enter the government complex.
Meanwhile, the group of protestors wore masks and used umbrellas to try to block reporters, smashing doors with metal rods and barricades.
Condemning the incident, a spokesman for the Hong Kong government was quoted as saying, "Protesters who resort to violence must stop their acts immediately. The police will take appropriate enforcement action to protect public order and safety."
Hospitals and police have not yet confirmed the number of injuries from the clashes.
Earlier on Monday, the police, in a statement, said that the protesters had pelted officers with objects containing an "unknown liquid," which made their skin swollen and itchy. At least 13 security personnel were treated at hospital, the police added.
July 1, the anniversary of the handover, has always been marked by marches featuring hundreds of thousands of people who want to demonstrate Hong Kong's unique status and democratic characteristics.
But after weeks of unprecedented tensions in the semiautonomous territory, protesters saw the occasion as their final chance for a massive stand against a government they believe is still not working in their interests.
"We are exhausted," said a 22-year-old protester who did not want to disclose his name for fear of retribution from authorities.
"But today's march is special. We think it will be the last one that people will come out [to] on a large scale. We have to show our disappointment and anger," he added.
An hour into the planned afternoon march, police sent out a warning, discouraging people from joining the procession over fears of a "safety threat," but tens of thousands showed up in a procession that again shut down roads.
In recent weeks, Hong Kong has been shaken by huge demonstrations against a controversial extradition bill which many fear could be used to deport political activists and dissidents to mainland China.
The said bill was proposed on April 3, and its opposers argue that its controversial amendments will leave anyone on Hong Kong soil vulnerable to being grabbed by the Chinese authorities for political reasons or inadvertent business offences.
Hong Kong leader Carrie Lam promised her government would be "more open and accommodating."
( With inputs from ANI )