China has rebuked US Secretary of State Mike Pompeo for remarks he made on the 30th anniversary of the Tiananmen Square protest.
Mr Pompeo criticised China's human rights record and called for it to reveal how many died in the crackdown.
A Chinese embassy spokesman in Washington DC said his comments were "an affront to the Chinese people".
In 1989, a large political protest in Beijing triggered a brutal clampdown by the communist authorities.
The Chinese government has never said how many people died at Tiananmen Square, although estimates range from the hundreds to thousands.
On Monday, Mr Pompeo had urged China to "make a full, public accounting of those killed or missing to give comfort to the many victims of this dark chapter of history".
He also accused China of "[abusing] human rights whenever it serves its interests", giving the example of China cracking down on its minority Uighur people in the Xinjiang region.
Mr Pompeo said US "hopes have been dashed" of China becoming "a more open, tolerant society" through greater global integration.
On Tuesday, in a rare public reference to Tiananmen Square, the Chinese embassy said China had "reached the verdict on the political incident of the late 1980s long ago".
A spokesman said Mr Pompeo had "used the pretext of human rights" for a statement that "grossly intervenes in China's internal affairs".
It added that his remarks were filled with "prejudice and arrogance".
It also rebutted Mr Pompeo's comments about human rights in China, saying they were currently in their "best period ever" and that anyone who attempted to "patronise and bully the Chinese people... will only end up in the ash heap of history".
What happened in 1989?
More than one million pro-democracy protesters occupied Tiananmen Square in April 1989 and began the largest political demonstration in communist China's history. It lasted six weeks.
On the night of 3 June tanks moved in and troops opened fire, killing and injuring many unarmed people in and around Tiananmen Square.
Afterwards the authorities claimed no-one had been shot dead in the square itself.
How is the Tiananmen anniversary being marked?
Around the world, dozens of rallies are taking place to remember the victims and call for change.
In Hong Kong - a semi-autonomous region of China - 180,000 people are expected to turn out for a candlelight vigil on Tuesday evening.
US House Speaker Nancy Pelosi is expected to attend a rally in Washington DC later.
What is the situation in Beijing on the anniversary?
China has never held any official acts of remembrance for the Tiananmen Square protests.
Ahead of the anniversary, Defence Minister Wei Fenghe made a rare mention of the protests during a regional forum in Singapore.
"That incident was a political turbulence and the central government took measures to stop the turbulence, which is a correct policy," he said.
He added that because of the government's action at that time "China has enjoyed stability and development".
In Tiananmen Square itself on Tuesday, in central Beijing, security remained tight, with police checking the identification cards of commuters leaving the subway station.
Many foreign journalists have not been allowed onto the square, those who have been allowed in were warned not to take pictures.
China has escalated its routine censorship of all references to Tiananmen or 1989 in the run-up to the anniversary.
However, some in China are remembering the event in their own ways.
Chen Wei is one of several activists who will be fasting for 24 hours on Tuesday.
The former student organiser told The Guardian that fasting was the one thing that "could not be restricted" by authorities.