Hong Kong officials have revealed that 750 of the protesters arrested during four months of unrest are children, sparking outrage in the city, as anger continues to grow over the government’s increasingly hardline measures against demonstrators.

The semi-autonomous city’s number two official Matthew Cheung said at a press conference on Thursday it was “shocking and heartbreaking” that 750 out of the 2,379 people arrested – or nearly a third – since June were under 18, and 104 were under 16.

Cheung appealed to parents and teachers to admonish youngsters and tell them to refrain from “illegal or violent acts” and avoid getting injured or arrested, something that would “end up destroying [their] future”.

The high proportion of children arrested sparked outrage in the community.

“[The government] says this is ‘heartbreaking’ but doesn’t ask why. Youth is rising up. They know they’re fighting for their future against a dictatorial regime,” said Kong Tsung-gan, an author and well-known blogger, on Twitter.

“Totalitarianism is going to destroy our next generation, resist!” wrote another person on Twitter.

On Tuesday, Hong Kong leader Carrie Lam said after school term started in September, nearly 40% of those arrested were under 18, while 10% of those arrested last Sunday were under 15.

A growing number of children have been arrested or injured in the increasingly violent and radical protests in recent weeks.

A Hong Kong policeman fired at an 18-year-old high school student’s chest during heated, territory-wide protests on China’s National Day on 1 October, while a 14-year-old was shot in the thigh by a plainclothes police officer last Friday during protests against the anti-mask ban. In a recent protest, an 11-year-old was sent to hospital after sustaining an injury.

Lam announced last Friday that the government had invoked the Emergency Regulations Ordinance to pass a regulation forbidding the use of face masks. There are widespread fears that the government would introduce more draconian measures to suppress civil freedoms.

While Lam said she cared “deeply” for students, she insisted that they should not participate in violent attacks and the anti-mask ban was aimed at “helping parents, teachers and students recognise that they shouldn’t be engaged in these acts.”

Schools across Hong Kong required parents to sign a notice saying they understood masks should not be worn inside or outside school, despite the fact that the ban applies only to public protests or assemblies. The Secretary for Education, Kevin Yeung, told reporters on Friday that the Education Bureau has required schools to report the number of students who wear masks to school after the ban was announced but stressed it was not going after schools or students.

“When [young people] are on the streets fighting selflessly, they are called ‘criminals and rioters’,” said Kenneth Chan, a political science professor at Hong Kong Baptist University. “The gap between the young people and the officials is impossible to bridge now.”

“It is a total breakdown of trust between the government and young people. It can only get worse because Carrie Lam has nothing but harsh measures to suppress and intimidate the young people and their parents.”