Hong Kong police officials on Tuesday admitted to being overwhelmed by a new level of violence unleashed by anti-government protesters across the city on National Day – but insisted that the performance of the force was effective.

Police leaders said the response of officers – including the use of live bullets that left an 18-year-old student hospitalised with a gunshot wound to the chest – was proportional to the level of aggression that erupted in marathon citywide protests.

The latest day of urban carnage began with the National Day flag-raising ceremony in the morning and continued well into the night as violence and retaliation escalated across the city. At least 13 areas reported confrontations between protesters and police, 47 MTR stations suspended services and more than 25 shopping centres shut down.

Anti-government protesters blocked roads, set fires and threw firebombs, bricks and other projectiles at the police in areas around the city. A group of radical protesters was said to have thrown petrol bombs into an MTR station, while others damaged shops with links to the mainland and destroyed the offices of pro-government district councillors.

Police fought back with clouds of tear gas in at least six districts, the use of water cannons in two areas and six live rounds in Yau Ma Tei and Tsuen Wan.

More than 66 people were injured on Tuesday, including police officers who were splashed with corrosive liquid in Tuen Mun and two who sustained head wounds during fighting in Yau Ma Tei.

A police source told the Post that officers were overwhelmed by the new scale of violence but managed to remain effective. The source said more than 180 protesters had been arrested.

Another police source said the violence used by protesters on Tuesday was the most extreme that officers had faced since the crisis started in early June.

“The police response was proportional to the level of aggression used by protesters,” the second source said. “Hundreds of petrol bombs, stones and corrosive liquid has been thrown at police today in a coordinated manner across several districts designed to stretch police resources.”

At least 6,000 police officers were deployed around the city on Tuesday as the force braced for hard-core protesters intent on disruption that were described as “one step closer to terrorism”.

Even so, a police presence was hardly felt in some restive neighbourhoods, while in some areas officers were outnumbered by protesters.

The last citywide turmoil comparable to Tuesday was August 5, when rallies in seven districts became violent. The police later reported that they had used some 800 tear gas canisters, 140 rubber bullets and arrested 148 people. No live rounds were fired that day.