Hong Kong police clarified on Monday morning that "no raiding operation" had been conducted at the Hong Kong Polytechnic University (PolyU), after a raging clash with hundreds of radical protesters that lasted an entire day, through the night, and continued until 11 a.m. Monday. 

Protesters threw Molotov cocktails and set fire to an armored police vehicle outside campus.

On Sunday night, defiant protesters also set the Hung Hom flyover ablaze, which sits close to PolyU. They then threw petrol bombs at an armored police vehicle while police were busy dispersing crowds. 

Hong Kong Police issue warning after rioters set major blaze to flyover near university

The police have confirmed two open fire cases. Police fired one shot at a private car when the driver attempted to hit an officer twice late Sunday, and another one took place Monday, with a large number of rioters taking away one arrested suspect by attacking the police. According to the police statement, the lives of the officers were under serious threat in both cases and that's why they fired shots.

Police later appealed to protesters, calling everyone inside the university to "drop their weapons and dangerous items" and leave in an orderly manner. 

Student protester Owan Li accused the police of "starting the war this morning," saying that the police were trying to enter PolyU from three directions. Police have refuted the claims.

"We did not 'raid' the premises of the PolyU," the police said in a statement released on Monday morning. "Explosives, flammable substances, and dangerous goods also pose threats to anyone therein. Police appeal to everyone inside the campus to leave immediately."

Roughly 100 petrol bombs from extreme protesters have hit the police's water cannon trucks and armored vehicles, a local news agency reported.

Despite repeated warnings to leave campus, protesters remained inside and started a massive fire at the school entrance to fend off police.

After the fire was doused, radicals again attacked police from the Hung Hom flyover, who then fired tear gas in response.

The police confirmed using – for the first time – a long-range acoustic device (LRAD) during clashes, a sound device for anti-riot operations but rejected accusations that the device was "a weapon" that could potentially hurt humans. 

"Unlike what is said in individual media reports, the LRAD does not generate ultra-low frequency sound which will cause dizziness, nausea or a loss of sense of direction," Hong Kong police said on their official Twitter handle.

The Hong Kong Education Bureau announced on Monday afternoon that all schools across the city shall remain suspended on Tuesday, marking the sixth day straight for the mass class suspension that starting Thursday.

In the statement, the bureau said the decision was due to the poor traffic conditions, and also offered schools enough time to resume operations.

The bureau also urged students to stay away from violence and any unlawful activities during this time.

Former Chief Executive of HKSAR, Leung Chun-ying, described the riots as planned and brutal, while delivering condemnation in a statement by the Hong Kong Professional Teachers' Union.

He added that Hong Kong police had already shown restraint. And he viewed the teachers' union statement as "encouraging" rioters to use NON-lethal weapons against police. The former Chief Executive urged the Hong Kong Professional Teachers' Union to call on rioters to surrender.