China legislation on Hong Kong could lead to U.S. sanctions - White House

China's proposed national security legislation for Hong Kong could lead to U.S. sanctions and threaten the city's status as a financial hub, White House National Security Adviser Robert O'Brien said on Sunday.

"It looks like, with this national security law, they're going to basically take over Hong Kong," O'Brien said on NBC's "Meet the Press."

"And if they do ... Secretary (of State Mike) Pompeo will likely be unable to certify that Hong Kong maintains a high degree of autonomy and if that happens there will be sanctions that will be imposed on Hong Kong and China," he said.

U.S. government officials have said the legislation would end the Chinese-ruled city's autonomy and would be bad for both Hong Kong's and China's economies. They said it could jeopardise the territory's special status in U.S. law, which has helped it maintain its position as a global financial center.

"It's hard to see how Hong Kong could remain the Asian financial center that it's become if China takes over," O'Brien said. Global corporations would have no reason to remain, he said.

"One reason that they came to Hong Kong is because there was the rule of law, there was a free enterprise system, there was a capitalist system, there was democracy and local legislative elections," O'Brien said. "If all those things go away, I'm not sure how the financial community can stay there."