Hong Kong, Jan 8 : Joshua Wong, a prominent Hong Kong pro-democracy activist, was arrested on Friday over "subverting the state power" under the national security law which China imposed in the city last year. Opposition politician Tam Tak-chi was also arrested along with Wong, who was the head of disbanded Demosisto -- a pro-democracy group advocating the city's independence, Xinhua news agency reported. Both Wong and Tak-chi have already been put in jail. Wong was sentenced to 13 and a half months in prison last month for besieging the police headquarters in June 2019, and Tam is awaiting trial behind bars for multiple offenses. In August 2020, the 27-year-old activist was also charged for participating in a banned vigil marking the anniversary of the 1989 Tiananmen Square crackdown in China. The national security law was enacted in Hong Kong in June 30, 2020, to ban acts of secession, subversion, terrorism and collusion with foreign forces. /IANS