China on Wednesday announced it would sanction more than two dozen US citizens, including Mike Pompeo, the former Secretary of State, in response to "grave interference” over Taiwan. Among the 28 named were Mr Pompeo, as well as John Bolton, Donald Trump’s former National Security Advisor; Peter Navarro, former Director of Trade; and Steve Bannon, former White House chief strategist. Mr Pompeo, in one of his final acts in his White House role, on Monday held a conference with the president of Taiwan, the self-ruling island claimed by Beijing as its own. He also jettisoned longstanding guidelines limiting exchanges with Taiwanese officials. China’s foreign ministry said in a statement that "crazy actions that have gravely interfered in China's internal affairs." "These individuals and their immediate family members are prohibited from entering the mainland of China, Hong Kong and Macau. They and companies and institutions associated with them are also restricted from doing business with China," it added. Relations between the US and China, the world’s two biggest economies, have plunged to their lowest level in decades, with disagreements on issues including Taiwan, Hong Kong, human rights, the coronavirus pandemic, the South China Sea, trade and espionage. Beijing has said that Taiwan is the most important and sensitive issue in its relationship with Washington, and has previously announced sanctions on US companies selling weapons to Taiwan, though it has not been clear how, or if, they were enforced. China last year unveiled sanctions on 11 US citizens, including lawmakers from Mr Trump’s Republican Party, in response to Washington’s sanctions on Hong Kong and Chinese officials accused of curtailing political freedom in the former British colony. A day earlier Mr Pompeo had also accused Beijing of genocide. He said Trump’s administration determined China has committed “genocide and crimes against humanity” in its repression of Uighur Muslims in the far western region of Xinjiang, becoming the first country to publicly make the accusation. The decision will set newly sworn in president Joe Biden on an awkward footing with China and may force the issues to the front of his China agenda.