WASHINGTON (AFP) - The United States on Tuesday (June 2) accused China of muzzling Hong Kong by preventing a vigil to mark the Tiananmen Square protests, amid a heated feud between Washington and Beijing over the city's freedoms.

"If there is any doubt about Beijing's intent, it is to deny Hong Kongers a voice and a choice, making them the same as mainlanders. So much for two systems," Secretary of State Mike Pompeo wrote on Twitter.

Hong Kong authorities effectively barred the annual commemoration of the 1989 crackdown - a major gathering in contrast to the imposed silence on the mainland - by extending a ban on gatherings to prevent the spread of the coronavirus.

"We urge Hong Kong authorities to allow people to peacefully remember the Chinese Communist Party's victims," State Department spokeswoman Morgan Ortagus said.

Mr Pompeo last week certified that Hong Kong no longer was autonomous from China under US law after Beijing pushed ahead on a controversial new security law.

Hong Kong's pro-Beijing leader Carrie Lam earlier on Monday accused the US of double standards as President Donald Trump orders the use of force to disperse demonstrators against racial abuse.