Hong Kong scholars and educators warned about the brainwashing of the city's young minds by radical militants after the city's police foiled a bomb plot that mostly involved young students and aimed to blow up courtrooms, tunnels, railways and trash cans.

Their warning came on Wednesday after six of the nine arrested in the case were revealed to be four males and two females aged between 15 and 18. The major sponsor of the plot, who was among the nine arrested, was a staff member at a local university.

Police said the students were recruited through online platforms or at anti-government street booths and were promised they would be sent from the city after carrying out the bombing. Calling it a well-organized and detailed bomb plot that could have injured many, the police busted the radical group when some of them were in a guesthouse in Tsim Sha Tsui making triacetone triperoxide, a highly unstable and powerful explosive known as TATP, which had been used in many overseas terrorist attacks.

Wong Kwan-yu, chairman of the Hong Kong Federation of Education Workers and a local secondary school principal, cautioned that the involvement of the youngsters in the alleged crime showed that activists were using all means to infiltrate students to disseminate extremist ideas. Educators and parents needed to pay close attention to the daily activities and psychological state of students, he said.

Wong also was skeptical about the purported admiration for an assailant who attempted to murder a police officer on a busy Causeway Bay street on July 1. The man stabbed himself to death after leaving a 10-centimeter wound in the officer's back.

Wong said that the education community was full of indignation at the alleged attacker and his politically motivated supporters.

Their irresponsible actions, such as calling the knife assailant a "martyr" and even making children mourn for him, would "sow the seeds of hatred" in young minds, with uncontrollable consequences for their lives and society, Wong warned.

The plotters were "heinous" for using secondary school students to commit crimes, Chief Secretary for Administration John Lee Ka-chiu said at a media session after Legislative Council meetings.

In a letter to students and staff, Hong Kong Baptist University President Alexander Wai Ping-kong confirmed that one of the nine arrested was a staff member at the university, and said it would fully assist in the investigation.

Wai strongly condemned acts of terrorism and violence that "posed serious threats to the security and order of society and the nation". He reminded members of the university to "abide by the law at all times".

Lau Siu-kai, vice-president of the Chinese Association of Hong Kong and Macao Studies, said society as a whole should work with the city's police force to report suspicious situations-for their personal safety and in the public interest.

He said the cases have exposed the public to the brutality of the radicals. Lau said that over the past year, ever since the implementation of the National Security Law for Hong Kong, there has been a clear and broad consensus in society that strongly disdains violence and advocates stability.

Senior Counsel Ronny Tong Ka-wah said the July 1 attack did not bring any progress to society, only tragedy. The public uproar should send a clear and loud message to radicals that their perceptions of local politics and the means they resort to for political ends were not welcome in the city.

It should be clear to the public, he said, that the rhetoric of some opposition politicians that honored crimes or claimed that violence could lead them to desired results, was nothing but "absurd deception".