Media playback is unsupported on your device Media caption Thousands held a vigil in Hong Kong, but security remained tight in Beijing

China has made a formal complaint to the US after the White House urged it to account for the protesters who were killed during the Tiananmen massacre.

Foreign Ministry spokesman Hong Lei said he was "deeply dissatisfied" and had lodged "solemn representations".

Tens of thousands of people gathered in Hong Kong to mark the 25th anniversary of the massacre, but all mention of the event was forbidden in mainland China.

Hundreds died when the army suppressed a huge pro-democracy protest in 1989.

The crackdown was ordered after hardliners won a power struggle within the ruling Communist Party.

There has never been another protest of its magnitude in mainland China.

The authorities in Beijing were keen to make sure no-one tried to commemorate the events, and detained dozens of people in the run-up to the anniversary.

Tiananmen protests

From 1978, China opened up its economy to the world, but communists maintained total control over politics

In 1989, hundreds of thousands gathered in Beijing's Tiananmen Square to call for political reform

Protesters remained in the square for weeks while a power struggle raged within the ruling Communist Party

Hardliners prevailed and gave the order to remove the protesters by force; hundreds were massacred in nearby streets

Timeline: Tiananmen protests

Why the protests still matter

Chinese media quiet on anniversary

In pictures: Tiananmen protests

Struggling against Tiananmen censors

But numerous governments called on Beijing to use the anniversary to rethink its attitude to human rights.

"We call on Chinese authorities to account for those killed, detained, or missing in connection with the events surrounding June 4, 1989," the White House said in a statement.

During a regular news conference, Mr Hong did not refer directly to the Tiananmen protests.

But he said: "The US statement on that incident shows a total disregard of fact."

Image copyright AFP Image caption Despite the tight security, Chinese tourists poured into Tiananmen Square as usual

Image copyright AFP Image caption In Hong Kong, tens of thousands gathered to commemorate the protests

Later, state-run news agency Xinhua published a story quoting Mr Hong as saying China was "strongly dissatisfied with and firmly opposed" to the US statement.

"We have lodged solemn representations to the US side."

It was unclear what kind of protest Mr Hong had lodged. The US embassy was unavailable for comment.

The Chinese authorities classify the 1989 protests as counter-revolutionary riots and hold no memorial.

But in Hong Kong a large crowd joined the Tiananmen remembrance rally, which has been held every year since the massacre.