Hong Kong has awakened to the necessity of stricter national security education, amid widespread criticism of a local student union for lauding the so-called "sacrifice" of a terrorist who stabbed a police officer before killing himself last week, top university officials said.

The chairmen of the Councils of the UGC Funded Universities, which represents eight top universities in Hong Kong, issued a joint statement calling for nurturing of proper values among students and staff following a series of shockingly violent crimes.

"Given the highly volatile situation, it is particularly regrettable that some members of the community have attempted to legitimize and even glorify such acts of violence," the statement reads.

The statement came two days after the University of Hong Kong Students' Union Council passed a resolution saying they "appreciate the sacrifice" of the assailant and expressed their condolences over his "unfortunate passing".

On July 1, a man stabbed a police officer in a busy street and then plunged the knife into his own chest.

Earlier this week, six secondary school students were among nine people arrested over an alleged plot to set off homemade bombs in courts, tunnels and trash cans. Their patron and accomplices included at least two educators from a secondary school and a local university.

The university chairmen said these acts were not only an affront to the law, but had gone beyond the norms of public decency, morality and values.

"All university stakeholders have a duty to halt extremist thinking, and to distance themselves from violence, and instead adopt proper values," adds the statement.

Among the signatories is Arthur Li Kwok-cheung, chairman of the Council of The University of Hong Kong. In an interview with a local newspaper on Thursday, Li said he welcomed a national security probe into student union leaders, who must be held accountable for their behavior.

Tony Kwok Man-wai, former deputy commissioner of the Independent Commission Against Corruption, told China Daily that it is time for the university to demonstrate its firm stance against violence with deterrent actions. He recommended a high-profile internal inquiry by university management according to the university code, imposing penalties for misconduct, and if necessary amending the university code to conform with the national security law.

The comments came after days of condemnation from Hong Kong officials and educators. In a letter to all principals and teachers in the city, Secretary for Education Kevin Yeung Yun-hung said the radical students involved should be "harshly denounced" as they" failed to distinguish right from wrong".

"These students, who have received higher education, have failed the expectations of their parents, society and the university. They should be ashamed of their behavior," the city's Security Bureau noted in a statement. The case highlighted the importance of national security education and the SAR government's supervision of education institutions, the statement continued.

The University of Hong Kong, in a separate statement, said that "the portrayal of the stabbing of a police officer and the suicide of the attacker as 'sacrifice' sent a totally wrong message to society." It then condemned all forms of violence and opposed any speech or acts that promote and justify violence.

Following intense public criticism, the Council of the Hong Kong University Students' Union announced in the early hours of Friday they would revoke the motion and resign altogether.

Zhang Zhengyang, an MPhil student in Chemistry and member of the Chinese Students and Scholars Association at The University of Hong Kong, also supported the school management taking further actions. He said that the student union's latest remedy did not make up for the blow to the university's reputation, which was tarnished by suspicion of condoning violence and even advocating terrorism, which affected graduates' employment.

He also believed in the need to promote national security education. He acknowledged the inadequacy of such an effort within the campus, especially among the local students.