Protesters who turned Hong Kong into a battleground on Feb 9 were determined to cause mayhem with flammable liquids and by blocking firefighters, David Lai Man-hin, the city's director of fire services, said on Thursday.

Twenty-two reports of fire were received that night and responses to all alarms were delayed by five to 60 minutes because of the protesters, who were throwing bricks and bottles, according to Fire Service Department statistics.

Some protesters even used flammable liquids, making it harder to control the situation, Lai said. A liquefied petroleum gas taxi was also set on fire, putting people in the vicinity in great danger if the situation had not been controlled by firefighters, Lai said.

Lai vowed to review the emergency management mechanism and consider equipping front-line firefighters with more portable tools.

The rioters' behavior triggered concerns about escalating violence and radicalization in the city. Local political analyst Song Sio-chong said the riot was predictable to some extent after the 79-day illegal "Occupy" movement in 2014. He thought the punishment of those organizers and active demonstrators was not heavy enough, as the majority were only sentenced to imprisonment for several days, which failed to deter them.

They are waiting for every chance to release their anger at society, Song said.

According to Hong Kong police statistics, 70 percent of the 42 protesters who were arrested and charged after the Mong Kok riot were younger than 30.

Explaining the reason behind the violence and radicalization, Song suggested the city's youth, who are facing a narrower social ladder than their parents' generation, could not cope with the current situation and refuse to put in effort to change it, instead putting the blame on society.

Meanwhile, in this Internet era, people are more likely to get confined in their own social networks, which narrows their sources of information, Song said. Thus many become deeply-influenced by radical ideology delivered by some local media, publications, films and online videos, Song said.

His opinion was echoed by Legislative Council member Priscilla Leung Mei-fun.

At a Legislative Council meeting on Thursday, she cited a local publication that compared the riot with "a sacrifice for the future", stressing that such kind of incitement is a great threat to the city's law and order.

Local education expert Li Hui also pointed out the failure in the city's education reform back in 2000, in which the authority removed a Chinese history course from the compulsory list and introduced a Liberal Studies course without comprehensive social and historic background. This resulted in young people's ungrounded criticism of society.

Li urged the authority to review its education policy.