Hong Kong police said on Sunday they had detained eight people near a park, four of them for "seditious intention and disorderly conduct", as authorities tightened security on the 34th anniversary of the 1989 Tiananmen Square crackdown.

Restrictions in Hong Kong have stifled what were once the biggest vigils marking the bloody crackdown by Chinese troops on pro-democracy demonstrators, leaving cities like London, New York, Berlin and Taipei to keep alive the memory on the June 4 anniversary.

Commemorations are expected on Sunday in at least 30 places in North America, Europe and Asia.

The eight people were detained near Victoria Park, where for years after 1989 democracy activists gathered on the Tiananmen Square anniversary.

Among them was artist Sanmu Chan who chanted "Do not forget June 4. Hongkongers don’t be scared", as police led him away on Saturday evening, according to a video clip seen by Reuters.

The police said the eight had been detained after "displaying protest items loaded with seditious wordings, chanting and committing unlawful acts".

Hong Kong activists say such police action is part of a broad campaign by China to end dissent in the city that was promised special freedoms for 50 years under a "one country, two systems" formula when former colonial power Britain handed it back in 1997.

Security is significantly tighter across Hong Kong this year, with up to 6,000 police officers deployed, including riot and anti-terrorism officers, the public broadcaster said.

Senior officials have warned people to abide by the law.

"Police are highly concerned about some people attempting to incite and provoke others to commit illegal acts that endanger national security, public order and public safety," police said in a statement.

'CLEAR CONCLUSION'

Despite the warnings, some individuals including some book shop owners, have been quietly marking June 4.

Jailed Hong Kong activist Chow Hang-tung, one of the leaders of a group called The Alliance, which used to organise Hong Kong's annual June 4 vigils before it was disbanded in 2021, said on Facebook she would hold a 34-hour hunger strike in prison.

In mainland China, any mention of the Tiananmen Square crackdown - where troops opened fire on pro-democracy protesters, killing hundreds if not thousands, according to rights groups - is taboo and the subject is heavily censored.

Foreign Ministry spokeswoman Mao Ning, asked about the government's response to events around the world to mark the anniversary, told a regular briefing in Beijing on Friday that the government had already "come to a clear conclusion about the political turmoil in the late 1980s".

In democratically governed Taiwan, the only part of the Chinese-speaking world when the anniversary can be marked freely and openly, activists will hold a memorial at Taipei's Liberty Square, alongside other activities including a play on Tiananmen by a Hong Kong playwright.

Vice President William Lai, the ruling Democratic Progressive Party's presidential candidate in an election next January, wrote on his Facebook page that what happened in Beijing in 1989 must be discussed and remembered.

"The event commemorating June 4 has continued to be held in Taipei, which shows that democracy and authoritarianism are the biggest differences between Taiwan and China," he said.

(Writing by James Pomfret; Editing by Robert Birsel)