Ten violent activists were sentenced to up to 51 months in prison on Thursday for their role in the 2016 Mong Kok riot, in which 130 people were injured, including 90 police officers.

Nine of the defendants received prison sentences of 28 to 51 months, and a teenager who was 17 years old at the time will be sent to a training center. The cases of dozens of others arrested in connection with the riot have been handled separately.

At the West Kowloon Magistrates' Courts, Magistrate Kwok Wai-kin emphasized that "unlawful violence is unacceptable in any society that exercises rule of law".

Punishment sufficiently harsh to be a deterrent that will protect the public and prevent similar cases was the primary consideration in sentencing the 10, Kwok said.

He said that the sentences were decided on in response not only to the individual acts but also to the serious social impact the defendants had made as a group.

The magistrate said the court would not participate in political debate, meaning that the background of the riot and the political beliefs of the defendants would not be taken into consideration in determining the sentencing.

Mo Jia-tao, 19, who had hurled bricks at police officers more than 11 times, got the longest sentence of 51 months in prison.

Kwok said Mo's actions involved "very serious" violence and such law-defying acts would send "wrong messages" to Hong Kong's young people, who might think they could do anything without restrictions. Mo was convicted of two counts of rioting and one count of criminal damage to a police car.

In the early morning of Feb 9, 2016, all the defendants participated in an unlawful assembly in Mong Kok, breaching the peace by hurling bricks pried from the pavement and setting fires in garbage bins, Kwok said.

Up to 47 police officers were injured in the specific incident, in which the 10 activists participated, and a police car was also damaged, causing a loss of HK$26,000($3,300) to the special administrative region's government.

All 10 defendants were remanded to Lai Chi Kok Reception Centre after being sentenced on charges that included rioting, criminal damage and assaulting police.

The trial has taken almost a year. The case also involves an 11th person identified as acting along with the other 10, but whom police were unable to detain.

The Mong Kok riot－the first such violent disturbance since Hong Kong's return in 1997－involved hundreds of masked participants.

Among the dozens arrested, the person receiving the harshest punishment was a computer technician who was sentenced to 57 months in prison in a separate case.