China has tightened access to Tiananmen Square in central Beijing on the anniversary of 1989 pro-democracy protests

Police in Hong Kong have detained several pro-democracy activists on the anniversary of the Tiananmen Square massacre. Authorities have banned public commemoration of the 1989 incident, which saw China crush peaceful protests in Beijing with tanks and troops. However, candlelight vigils have been taking place in other cities worldwide.

RESENDING THIS STORY TO CLARIFY PROTESTERS, INCLUDING ALEXANDRA WONG, WERE GENERALLY DETAINED, WITH ONLY FOUR ARRESTED BY HONG KONG POLICE.A pro-democracy activist was among scores detained by Hong Kong police along with at least four people arrested as authorities tightened security on the 34th anniversary of China's bloody crackdown on protesters in Tiananmen Square.

Hong Kong police detained more than 20 people on Sunday, the 34th anniversary of the crackdown on protesters in Beijing’s Tiananmen Square, as authorities took a forceful approach to prevent any public commemoration of the deadly event.

For the past 34 years, the height of “ politically sensitive periods ” for the Chinese government invariably falls around the same day: June 4, the anniversary of the Tiananmen Square massacre in Beijing. And, as use of the internet has become increasingly ubiquitous in China, online surveillance and censorship go into overdrive during this period.

Hong Kong police have arrested or detained more than a dozen protesters at the park that once hosted annual memorial ceremonies for the Tiananmen Square crackdown anniversary.

Hong Kong police said they detained 23 people on Sunday for "breaching public peace" and arrested a 53-year-old woman for "obstructing police officers" as authorities ramped up security for the 34th anniversary of the 1989 Tiananmen Square crackdown.