A Hong Kong activist whose beating by police was caught on video has been sentenced to five weeks in prison on charges related to the confrontation, stirring outrage among pro-democracy supporters.

Local news reports said Monday that Ken Tsang was sentenced on charges of assaulting police and resisting arrest stemming from the October 2014 incident at the height of street protests that gripped the city.

Tsang, who prosecutors said splashed an unknown liquid on officers, was found guilty last week.

A local TV station filmed police officers carrying Tsang away in handcuffs and then punching and kicking him in a dark corner of a public park during a pre-dawn clash over Beijing's plans to restrict elections.

Seven officers are to go on trial this week over the beating.