China has suspended U.S. warship visits to Hong Kong and vowed to sanction some human-rights organizations over a law supporting the territory’s protesters. However, Beijing’s retaliation to U.S. support of pro-democracy demonstrators avoided measures related to trade. Chinese Foreign Ministry spokeswoman Hua Chunying said Monday that U.S. groups targeted for sanctions included the National Endowment for Democracy, Human Rights Watch, and Freedom House. Bloomberg News reports China will also suspend further Hong Kong port visits by U.S. Navy ships. The spokeswoman didn’t explain how China would sanction the rights groups, which are already banned from operating on the mainland. “This seems to be an empty threat because these groups don’t operate inside mainland China,” said Patrick Poon, a Hong Kong-based China researcher at Amnesty International. An economic slowdown in China has given President Xi Jinping limited options for hitting back at Washington’s support.