FOREIGN Secretary Jeremy Hunt today warned Beijing of "serious consequences" over mounting tensions on the streets of Hong Kong.

His warning came hours after Chinese riot cops fired tear gas at Union Jack-waving demonstrators in the former British colony.

17 Hong Kong police opened fire with tear gas in the early hours of this morning Credit: AFP or licensors

17 Britain has urged British flag-waving rioters to stop the violence, despite 'unwavering' support Credit: Alamy Live News

The wannabe PM warned there would be a diplomatic showdown if the Sino-British declaration on Hong Kong was not honoured by Beijing.

"The UK signed an internationally binding legal agreement in 1984 that enshrines the one country two systems rule, enshrines the basic freedoms of the people of Hong Kong and we stand four square behind that agreement, four square behind the people of Hong Kong," he told BBC TV.

"There will be serious consequences if that internationally binding legal agreement were not to be honoured."

Earlier China told the UK to "stop interfering" in its "internal affairs" .

A Chinese government spokesman was quoted as saying Britain needed to "know its place and stop interfering" in what was a "purely internal affair."

The UK earlier vowed "unwavering" support for the half a million people demonstrating against Chinese rule in Hong Kong but has urged against using violence.

And Mr Hunt pledged to continue his support despite China's warning.

"No violence is acceptable but HK people MUST preserve right to peaceful protest exercised within the law, as hundreds of thousands of brave people showed today," he added.

17 Riot cops fire tear gas at protesters near the government HQ Credit: AFP or licensors

17 Riot police clash with protesters as they arrive to disperse protesters from the Legislative Council Building Credit: EPA

17 Jeremy Hunt has reiterated his support for peaceful protest but warned of serious consequences

The European Union also urged anti-government protesters to use restraint.

"It is all the more important to exercise restraint, avoiding escalatory responses, and to engage in dialogue and consultation to find a way forward," the EU's diplomatic arm said.

Donald Trump also found himself in the firing line after he weighed in on the protests saying the demonstrators are "looking for democracy" but that "some governments don't want democracy."

In response, Chinese foreign ministry spokesman Geng Shuang said: "We deplore and strongly oppose the relevant country's gross interference in Hong Kong affairs and China's internal affairs."

He added Beijing warns "the relevant country to speak and act cautiously and stop interfering in Hong Kong's internal affairs in any form".

He also said the United States should "not in any form support those engaged in violence and breaking the law".

Hong Kong became a British colony at the end of the First Opium War in 1842.

Britain obtained a 99-year lease for the strategically important territory which expired in 1997.

Away from campaigning want to stress UK support for Hong Kong and its freedoms is UNWAVERING on this anniversary day. No violence is acceptable but HK people MUST preserve right to peaceful protest exercised within the law, as hundreds of thousands of brave people showed today. — Jeremy Hunt (@Jeremy_Hunt) July 1, 2019

Since then, Hong Kong has been part of China, but kept laws allowing citizens more freedoms than those enjoyed in the mainland.

Protesters forced their way into Hong Kong's parliament following outrage about a controversial new law which would allow enforced extraditions to mainland China.

Riot police inside the building donned gas masks and initially responded from above with pepper spray, but protesters unfurled umbrellas to shield themselves.

Soon after midnight police fired tear gas and drew their batons as they vowed to take back control of the Government building.

Beijing accused protesters who vandalised Hong Kong's parliament of "serious illegal actions" that "trample on the rule of law".

The spokesman said the Beijing government was "extremely dissatisfied" with the way Britain had "continuously gesticulated" about Hong Kong.

But as tens of thousands of protesters took to the streets, Mr Hunt said the Government would continue to speak out in support of their rights.

Protesters storm inside government building during the anniversary of Hong Kong's handover to China

While he said that violence was not acceptable, the right to peaceful protest within the law had to be protected.

He tweeted: "Away from campaigning want to stress UK support for Hong Kong and its freedoms is UNWAVERING on this anniversary day.

"No violence is acceptable but HK people MUST preserve right to peaceful protest exercised within the law, as hundreds of thousands of brave people showed today."

The Foreign Office stressed Britain was monitoring the agreement under which Hong Kong was handed over to China 22 years ago.

A spokeswoman said: "By monitoring its implementation we are acting responsibly in line with our commitments, not interfering.

"Hong Kong's rights and freedoms and high degree of autonomy underpin its success and prosperity.

"We will continue to stand up for these principles, including speaking out publicly and raising issues with the Chinese government when we have concerns."

SYMBOL OF DEFIANCE

Yesterday, protesters used a metal trolley and poles to storm into Hong Kong's Legislative Council building today and then raised the British colonial flag in a symbol of defiance.

Earlier hundreds of thousands of demonstrators had taken to the streets to mark the anniversary of the 1997 handover to Chinese rule, as anger over an extradition bill continues.

Demonstrators dressed in all-black and wearing hard hats and face masks smashed a large hole through the bottom of a floor-to-ceiling window.

Hundreds crowded the building's lobby, spray-painting messages on the walls and waving to the crowd outside from upstairs windows.

Footage taken outside the building shows the trolley being repeatedly smashed into the front door as police stand guard inside.

After they managed to get the trolley wedged into the damaged panel, police managed to grab it away from them.

But they eventually managed to batter their way in and footage shows the demonstrators walking through the shattered windows.

17 Protesters attempting to smash their way into Hong Kong's Legislative Council Credit: Reuters

17 Demonstrators also daubed the walls with anti-government slogans Credit: AFP

Hong Kong handover Hong Kong became a British colony with the end of the First Opium War in 1842. The British fought the war to preserve the right of the East India Company to sell opium into mainland China.

The establishment of the colony gave Britain control over a number of ports to which foreign merchants could deliver goods.

Britain obtained a 99-year lease for the territory in 1898, and relinquished control when that lease expired in 1997.

Hong Kong now operates as a semi-autonomous territory, with control over its own trade, tax, and immigration policy.

Under the terms of the 1997 handover, that status is protected until 2047.

What happens after then is currently undecided, but opponents of the Beijing government fear that China will seek to gain control of the territory.

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Inside protesters defaced the Bauhinia crest of Hong Kong with spray paint, and were videotaped destroying office equipment.

A black and white banner hoisted in the chamber read in Chinese: “Bow to protect rule of law. Oppose extradition.”

The violence came as the city’s leader Carrie Lam attended the annual ceremony, in which the Chinese and Hong Kong flags were raised together while two helicopters and a small flotilla passed by.

17 Demonstrators eventually managed to smash their way in Credit: AFP or licensors

17 A protester throws a portrait of a politician after protesters broke into the government HQ Credit: AFP

17 Demonstrators dressed in all-black and wearing hard hats and face masks stormed the building Credit: Reuters

17 Credit: AFP

A protester attempts to cover the Hong Kong emblem with a British colonial flag

17 Demonstrators also daubed the walls with anti-government slogans Credit: AFP

17 Protesters fixed a British colonial flag to the parliament podium after they broke into the government HQ Credit: AFP

17 Mr Hunt said that violence was not acceptable, the right to peaceful protest within the law had to be protected Credit: AFP

17 Demonstrators dressed in all-black and wearing hard hats and face masks smashed a large hole through the bottom of a floor-to-ceiling window Credit: Getty Images - Getty

17 Tens of thousands of people took to the streets to protest Credit: AP:Associated Press

17 A makeshift 'protest' memorial near government headquarters in Hong Kong Credit: AP:Associated Press