China's UK embassy has asked Twitter to "make thorough investigations" after its ambassador's official account liked a pornographic clip.
Liu Xiaoming's account also liked posts that criticised the Chinese Communist Party (CCP) and showed blindfolded Uighurs being detained.
Officials claimed that "anti-Chinese elements [had] viciously attacked" Mr Liu's account in a "despicable" plot designed to "deceive the public".
Twitter has yet to comment.
The activity first drew attention after the account liked a 10-second video posted by an adult-themed page containing clips with Chinese-language descriptions.
A London-based human rights campaigner flagged this to other Twitter users just after 09:00 GMT with a screenshot as proof.
The clip was subsequently unliked by whoever was controlling the account.
But some other tweets remained liked for a time before they too were reversed.
One included claims that officials had "paid lip service to non-interference" in order to get away with killing members of the Chinese public.
A second featured drone-captured footage of Uighur Muslims being taken to what the post described as a "concentration camp".
Beijing has previously denied holding large numbers of people from the ethnic minority in camps against their will in the western Xinjiang region.
And the ambassador denied his country was carrying out a programme of sterilisation of Uighur women, when he was shown the drone footage by the BBC earlier in the year.
Twitter is blocked within mainland China. But over the past year Chinese officials have become more active on the platform, and Mr Liu's account was created in October.
The app's likes are sometimes used as a kind of bookmark facility rather than to express support, and the heart-shaped icon that activates them can be easily selected by mistake.
Some of the social network's users have suggested the pornographic clip might have been liked by accident and then the others selected as part of a cover story.
But Chinese officials have dismissed the suggestion.
"The embassy has reported this to Twitter and urged the latter to make thorough investigations and handle this matter seriously," said a statement.
"The embassy reserves the right to take further actions and hope that the public will not believe or spread such rumour[s]."
Mr Liu's account now only has two likes - both related to tweets it posted in 2019.
It has also tweeted a proverb in reaction to the affair, suggesting the ambassador is not concerned about being attacked: "A good anvil does not fear the hammer."