(Bloomberg) -- Hong Kong police made their first arrest on Wednesday less than 24 hours after China imposed a sweeping new national security law in the territory.

A man was arrested for holding a Hong Kong independence flag in the central Causeway Bay neighborhood, the police force tweeted Wednesday. The legislation has raised fears about the financial hub’s autonomy from the mainland and the preservation of its basic freedoms, including of speech and the press.

Chinese officials earlier Wednesday described the law as a “sword of Damocles” hanging over its most strident critics.

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