The University of Hong Kong announced on Tuesday it was cutting ties with its student union after a strong backlash against the union members' glorification of an attempt to kill a police officer on July 1.

The university made the move just hours after Hong Kong Chief Executive Carrie Lam Cheng Yuet-ngor said university authorities should take further action against such behavior. The council of the university's student union had been criticized after it openly paid tribute to an assailant who stabbed a police officer on a busy street before killing himself.

Lam said she was outraged by student resolutions that "almost salute the coldblooded criminal suspect" and felt ashamed for the university, which she serves as chancellor.

The student union council withdrew the motion on Friday, two days after passing it by 30 votes to 0 to "appreciate the sacrifice" of the assailant and express its condolences over his "unfortunate passing".

At a media briefing on Tuesday, Lam said she would support follow-up investigations by the city's police force if it decides there is a case to look into.

The University of Hong Kong then issued a statement saying it would "solemnly conduct an investigation" into the incident, and vowed to "take action against the students concerned" based on the investigation outcomes.

It did not reveal the detailed procedure or the potential penalties. The chairman of the university council, Arthur Li Kwok-cheung, said earlier that expulsion of those who approved the motion was a possible outcome.

The university said it would no longer recognize the current role of the student union on campus. The student union had been an independent registered association since 1949 and maintained an important place in the university's student affairs, including running campus media and leading 130 affiliated student organizations.

A dedicated team will be set up to fill in for the student union to coordinate and handle students' activities, the university said.

In April, the university distanced itself from the student union by withdrawing services and facilities after criticizing the body for "utilizing the university campus as a platform for its political propaganda "and bringing the university "legal risks".

The university also urged its students to uphold rationality and proper values, focus on their studies and make contributions to society.

Meanwhile, a 15-year-old boy will face a charge of conspiracy to commit terrorism under the National Security Law for Hong Kong on Wednesday. He will become the fourth secondary school student to appear in court in the case. A total of nine students and five adults have been arrested since July 5 over their alleged involvement in a foiled terror plot to blow up local courts and transportation networks.

Lam said on Monday that it is worrying to see young students being used to commit crimes.

She called on the city's adults to guide young people to have a stronger sense of national identity and nurture positive values.

In an effort to strengthen youngsters' national identity and national security awareness, the city's education bureau provided all kindergartens with textbooks on the national security law, which were compiled by legal and educational experts on the Chinese mainland. Primary and secondary schools had received copies earlier.

In a letter to the kindergartens on Monday, the bureau stressed the schools should help the toddlers understand that Hong Kong is part of the country and their identity is Chinese.

This month also saw a number of mainland-produced TV dramas and movies aired in Hong Kong in celebration of the centenary of the Communist Party of China. David Chiu Tat-cheong, the owner of Cable TV, which has broadcast the hit series Age of Awakening since Monday, said he hoped Hong Kong audiences, especially young people, will learn from the patriotic youth in history and strive to contribute to a better city and the country.