China's internet erupted in mirth at America's troubled democracy after supporters of President Donald Trump broke into the US Capitol, comparing the chaos to the Hong Kong anti-government protests of 2019.

On Thursday morning, state media tabloid Global Times tweeted side-by-side photo comparisons of Hong Kong protesters occupying the city's Legislative Council Complex in July 2019 with Wednesday's Washington riots.

The latter saw hardcore Trump fans invade the US Capitol to protest the election defeat, taking selfies, scuffling with security and ransacking parts of the building.

"@SpeakerPelosi once referred to the Hong Kong riots as 'a beautiful sight to behold'," the Global Times said in the tweet, referring to Speaker of the House Nancy Pelosi's June 2019 comment about Hong Kong's mass pro-democracy demonstrations, which were mostly peaceful at that time.

"It remains yet to be seen whether she will say the same about the recent developments in Capitol Hill."

China's Communist Youth League also described the unrest as a "beautiful sight" on the Twitter-like Weibo platform.

The hashtag "Trump supporters storm US Capitol" pinballed across Weibo on Thursday, racking up 230 million views, as users compared the global support for Hong Kong's protesters with the outpouring of condemnation for the pro-Trump mob.

"At present, all European countries' leaders have shown double standards and condemned it (Washington rioting)," read one Weibo comment which gained over 5,000 likes.

"I don't know what kind of double-standard reports will be carried by Hong Kong or Taiwan media this time." 

"What happened in the Hong Kong Legislative Council last year is being repeated in the US Capitol," wrote another user in a comment with over 4,500 likes. 

While the tactics were similar, there are stark differences in the causes and motivations of the two legislature stormings.

Hong Kong protesters broke into their legislature to demand full democracy and halt an unpopular bill that was being pushed through by the city's unelected leadership.

The semi-autonomous Chinese city is not a democracy, the cause of years of popular protests. 

China has since responded with a crackdown, imposing a harsh security law on the restless city, arresting scores of critics and smothering dissent.

In contrast, those storming the US Capitol were trying to overturn the results of what has been declared a free and fair presidential election.

US President-elect Joe Biden said the US rioters were undermining democracy by trying to overturn Trump's defeat in November's election.