With an extensive show of force on Wednesday, officers in riot gear confronted demonstrators who gathered in Hong Kong’s main shopping district, making arrests, firing pepper spray and hoisting a purple banner warning protesters could be in violation of the new law. The man arrested for holding a Hong Kong independence flag was violating the new law, police said on Twitter…

At least one demonstrator waved an American flag, a widely used protest symbol here, while others waved flags advocating Hong Kong independence. Among those arrested was Andrew Wan, a Democratic Party member of the city’s legislature, according to his assistant.

In a sign of how wide-reaching the new law may be, police in a statement said they noted some protesters chanting, “Hong Kong independence, the only way out.” They said such slogans are “suspected to be inciting or abetting others to commit secession” and may violate the new national security law.