BEIJING (Reuters) – China said on Monday U.S. military ships and aircraft won’t be allowed to visit Hong Kong, and also announced sanctions against several U.S. non-government organizations for encouraging protesters to “engage in extremist, violent and criminal acts.”

The measures were announced by China’s Foreign Ministry in response to U.S. legislation passed last week supporting anti-government protesters. It said it had suspended taking requests for U.S. military visits indefinitely, and warned of further action to come.

“We urge the U.S. to correct the mistakes and stop interfering in our internal affairs. China will take further steps if necessary to uphold Hong Kong’s stability and prosperity and China’s sovereignty,” said ministry spokeswoman Hua Chunying said at a daily news briefing in Beijing.

China last week promised it would issue “firm counter measures” after U.S. President Donald Trump signed into law the “Hong Kong Human Rights and Democracy Act,” which supports anti-government protesters in Hong Kong and threatens China with potential sanctions.

There are fears that the row over Hong Kong could impact efforts by Beijing and Washington to reach preliminary deal that could de-escalate a prolonged trade war between the two countries.

The U.S.-headquartered NGOs targeted by Beijing include the National Endowment for Democracy, the National Democratic Institute for International Affairs, the International Republican Institute, Human Rights Watch, and Freedom House.

“They shoulder some responsibility for the chaos in Hong Kong and they should be sanctioned and pay the price,” said Hua.

In more normal times, several U.S. naval ships visit Hong Kong annually, a rest-and-recreation tradition that dates back to the pre-1997 colonial era which Beijing allowed to continue after the handover from British to Chinese rule.

Visits have at times been refused amid broader tensions and two U.S. ships were denied access in August.

The USS Blue Ridge, the command ship of the Japanese-based Seventh Fleet, stopped in Hong Kong in April – the last ship to visit before mass protests broke out in June.

Foreign NGOs are already heavily restricted in China, and have previously received sharp rebukes for reporting on rights issues in the country including the mass detention of Uighur Muslims in Xinjiang.

(Reporting by Cate Cadell and Beijing Monitoring Desk; Editing by Tom Hogue & Simon Cameron-Moore)