BEIJING (Reuters) - China will impose sanctions on four people with links to U.S. democracy promotion efforts, it said on Monday, over what it called interference in the Asian financial hub of Hong Kong, following U.S. strictures on four Chinese individuals. Relations between the two nations have deteriorated to their worst in decades during outgoing U.S. President Donald Trump’s four-year term, with disputes simmering over issues from trade and technology to Hong Kong and the coronavirus. China’s foreign ministry identified the four as John Knaus, senior director of the National Endowment for Democracy (NED); Manpreet Anand, a regional director of the National Democratic Institute (NDI); Kelvin Sit, the NDI’s program director for Hong Kong and Crystal Rosario, a specialist at the NDI. From Monday, they will be banned from entering China, a foreign ministry spokeswoman said in the Chinese capital. “The U.S. behaviour blatantly interferes in Hong Kong affairs and grossly interferes in China’s domestic affairs,” the spokeswoman, Hua Chunying, told a regular news briefing. “It violates basic norms governing international relations, and China firmly rejects and condemns this.” She gave no further details of the four, but the National Democratic Institute is a U.S. non-profit with more than three decades of support for democratic institutions and practices across the world, it says on its website. This month, the United States said it was imposing sanctions on four more Chinese individuals tied to actions over the former British colony, which returned to Chinese rule in 1997. The move followed Hong Kong’s expulsion of four opposition members from its legislature after Beijing gave city authorities new powers to curb dissent. It triggered mass resignations by Hong Kong’s pro-democracy opposition lawmakers. China denies limiting rights and freedoms in mainly autonomous Hong Kong but authorities there and in Beijing have moved swiftly to stifle dissent after anti-government protests flared in June last year and plunged the city into crisis.