China has warned the UK not to "interfere in its domestic affairs" amid a growing diplomatic row over the recent protests in Hong Kong.
Its UK ambassador said relations had been "damaged" by comments by Foreign Secretary Jeremy Hunt and others backing the demonstrators' actions.
Liu Xiaoming said those who illegally occupied Hong Kong's parliament should be "condemned as law breakers".
The ambassador was later summoned to the Foreign Office over the remarks.
A Foreign Office spokesman said Sir Simon McDonald, permanent under secretary and head of the diplomatic service, told the ambassador his comments were "unacceptable and inaccurate".
Earlier, Prime Minister Theresa May said she had raised concerns with Chinese leaders.
Weeks of mass protests in the territory over a controversial extradition bill exploded on Monday, when a group of activists occupied the Legislative Council building for several hours after breaking away from a peaceful protest - raising the colonial-era British flag.
Critics say the extradition bill could be used to send political dissidents from Hong Kong to the mainland.
Demonstrators have also broadened their demands to include the release of all detained activists and investigations into alleged police violence.
In the middle of the demonstrations, Mr Hunt pledged his "unwavering" support to the ex-British colony and its citizens' freedoms.
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
In a series of broadcast interviews and posts on social media, Mr Hunt repeated the message that the protesters should refrain from violence, but urged China to listen to the concerns of the Hong Kong people.
Beijing has made a formal complaint about Mr Hunt, accusing the Conservative leadership contender of "colonial-era delusions".
But Mr Liu said he was "disappointed" by the UK's response.
He said the countries' relationship was based on mutual respect and suggested there would be further "problems" if the UK did not recognise China's sovereignty over Hong Kong, its "territorial integrity and principle of non-interference in domestic affairs".
He said it was "hypocritical" of UK politicians to criticise the lack of democracy and civil rights in Hong Kong when, under British rule, there had been no elections nor right to protest.
The recent unrest, he added, was "not about freedom but about breaking the law".
In response, Mr Hunt said good relations between countries were based on "honouring the legally binding relationships between them" - a reference to a 1984 treaty between the UK and China which paved the way for sovereignty over the territory to pass back to Beijing.
Message to Chinese govt: good relations between countries are based on mutual respect and honouring the legally binding agreements between them. That is the best way to preserve the great relationship between the UK and China— Jeremy Hunt (@Jeremy_Hunt) July 3, 2019
The Joint Declaration, signed by Margaret Thatcher and the then Chinese Premier Zhao Ziyang, set out how the rights of Hong Kong citizens should be protected in the territory's Basic Law under Chinese rule.
Hong Kong has, since 1997, been run by China under a "one country, two systems" arrangement guaranteeing it a level of economic autonomy and personal freedoms not permitted on the mainland.
Analysis: By James Landale, BBC diplomatic correspondent
The ambassador gave the British government both barrels at his press conference earlier.
What's fascinating is there was no pretence, no attempt to gloss this over at all. This was visceral and system-wide. This is merely the British side of things, the same message is coming from Beijing and Hong Kong too. There is definite push-back from the whole Chinese machine.
The British are so infuriated that they've summoned the ambassador almost immediately to give him a dressing down.
What was a war of words now risks becoming a substantial issue between the two countries.
The Foreign Office has said it continues to make it clear to the Chinese government, both in public and private, that the rights of Hong Kong residents must be fully respected.
Speaking on Wednesday, Theresa May said she had raised her concerns directly with Chinese leaders at the recent G20 meeting.
"It is vital that Hong Kong's high degree of autonomy and the rights and freedoms set down in the Sino-British joint declaration are respected," she told MPs.
Successive UK governments have heralded a "golden era" in economic relations with China, with growing levels of trade and foreign investment.
But critics say this has come at the expense of turning a blind eye to human rights violations in China and Beijing's increasing economic nationalism.