Dozens of protestors were detained in Hong Kong in connection with the 34th anniversary of the Tiananmen Square massacre, according to reports. Key details: A total of 23 people — 11 men and 12 women — were taken into custody on Sunday for “breaching the public peace.

Tiananmen Square memorials have long been illegal in mainland China, but the crackdown in Hong Kong is a more recent development.

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.

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.

With candlelight vigils to the victims of the 1989 crushed student uprising in Beijing now only a memory, the anniversary is also a reminder of the freedoms Hong Kong has lost.

Hong Kong police have detained eight people on the eve of the 34th anniversary of China’s Tiananmen Square crackdown

Many Hong Kongers are trying to mark the event in private ways because it is unclear what authorities might consider subversive.