Hundreds gathered in Taiwan on Tuesday night to commemorate the 35th anniversary of China's deadly crackdown at Tiananmen Square, after the island's President Lai Ching-te vowed that the memory of those killed would not disappear.

Chinese troops and tanks forcibly dispersed peaceful protests in Beijing's Tiananmen Square on June 4, 1989, quelling huge, weeks-long demonstrations demanding greater political freedoms.

Decades on, China still censors any mention of the crackdown.

On Tuesday evening, hundreds of people converged around Taipei's Liberty Square for an annual vigil, placing candles on a laid-flat banner with the date of the crackdown, while listening to activists criticise the Chinese government for alleged rights abuses.

"We will continue to work hard to keep this historical memory alive and touch everyone who cares about Chinese democracy," Lai, Taiwan's newly inaugurated president, said in a Facebook post Tuesday.

"Because this reminds us that democracy and freedom are not easy to come by, we must... respond to autocracy with freedom, face the expansion of authoritarianism with courage."

China has repeatedly lashed out against Lai, branding him a "dangerous separatist" and a "saboteur of peace and stability".

His inauguration in May prompted Beijing to launch military drills around the self-ruled island.

Lai's Democratic Progressive Party has long defended the sovereignty and democracy of Taiwan, which has its own government, military and currency.

"China is becoming more and more authoritarian and (Chinese President) Xi Jinping is like an emperor," said Taipei vigil attendee Vincent Lee, 46.

"I think commemorating June 4th is a way to protect Taiwan's democracy and freedom against China's dictatorship... we need to protect Taiwan's free and democratic values."

China's Tiananmen crackdown killed hundreds of people, with some estimating the death toll was higher than a thousand.

Beijing described the events as riots, while rights groups and exiled dissidents depict it as a massacre of innocent people, including many students.

Many young people today in China are unaware of the 1989 events due to wide-reaching censorship.

In Beijing on Tuesday, tourist groups visited Tiananmen Square donning matching neon hats and posing for pictures beside the mausoleum of China's founding leader Mao Zedong.

The Tiananmen Mothers, a group comprised of relatives of victims of the 1989 crackdown, called for the tragedy to be resolved "in an open, fair and just manner" in a statement.

"We shall never allow your lives to be sacrificed in vain. The historical tragedy must not repeat," it said.

Asked about the anniversary on Tuesday, a Chinese foreign ministry spokesperson said "the Chinese government has long since reached a clear conclusion".

"We have always opposed anyone using this as a pretext to attack and smear China and to interfere in China's internal affairs," spokeswoman Mao Ning said.

Meanwhile, the European Union and United States said separately on Tuesday that they stand "in solidarity" with the Tiananmen Square victims and rights activists continuing to fight for greater freedoms.

In Hong Kong, once the sole place on Chinese soil where public commemoration was allowed, an annual Tiananmen vigil has been banned since Beijing imposed a national security law to quell dissent in 2020.

The mass mourning was once a symbol of Hong Kong's unique freedoms.

In the week leading up to the anniversary, Hong Kong police arrested eight people over commemorating the Tiananmen crackdown on social media, with authorities accusing them of publishing "seditious" online posts.

AFP journalists on Tuesday saw scores of police patrolling the Causeway Bay area, where tens of thousands previously gathered each year to mourn the dead.

Authorities stopped and searched shoppers, including confused Chinese tourists, with AFP journalists witnessing some being taken away.

In a statement issued early Wednesday, police said that four had been arrested around the area.

One of them was a 68-year-old woman arrested for "offences in connection with seditious intention", a crime under Hong Kong's new controversial security law Hong Kong enacted in March.

The statement said five others were removed "for investigation of disrupting public peace", and released soon after.

Earlier in the evening, seated on a park bench reading the play "May 35" -- a coded reference to June 4 -- theatre worker Tsang said she "came here for those who can't speak out for themselves".

"I want to show that people still remember," she told AFP. "People may not come out because they are worried, but there is still a seed in their hearts."(Daily Mail)