China on Tuesday sanctioned Mike Gallagher, a former Republican member of Congress from Wisconsin, who has shown support for Taiwan.
Gallagher will be banned from entering China, any assets he holds in the country will be frozen and he will be barred from various exchanges with Chinese organizations and individuals, the country's Foreign Ministry announced.
The sanctions come a day after US Secretary of State Antony Blinken congratulated Taiwan's new president, Lai Ching-te, on his inauguration Monday.
China claims the self-ruled island of Taiwan as its own territory, to be annexed by force if necessary, and bristles at other countries' exchanges with Taipei.
Gallagher, who stepped down in April, led the House pushback against the Chinese government, including helping to pass a bill that could ban popular video app TikTok if its China-based owner doesn't sell its stake.
In February, Gallagher led a Congressional delegation to Taiwan in a visit that sought to assure Taipei of Washington's continued support.
The United States, like most countries, doesn't recognize Taiwan as a country but is bound by its own laws to ensure the island can defend itself.