Media outlets in Hong Kong have reported that 30 people living abroad are on a wanted list on suspicion of violating the national security law for the territory.
Hong Kong media, as well as China's state-run Central Television, say people now living in Britain, the United States and other places are accused of inciting secession or colluding with foreign forces to endanger national security.
People on the list include former Hong Kong lawmaker Ted Hui, who has been charged with disrupting proceedings at the legislative council. Hui traveled to Europe after he was released on bail, and announced earlier this month that he was going into exile.
Nathan Law, a prominent pro-democracy activist who has relocated to Britain, is also on the list.
Pro-democracy protests in Hong Kong have been severely restricted since the law was enacted in June.
Authorities are also intensifying their crackdown on activities outside Hong Kong, as the law stipulates that acts abroad and foreigners can be prosecuted.