This article is more than 1 year old

This article is more than 1 year old

Chinese authorities have detained dozens of people as part of a ramped-up annual crackdown ahead of the anniversary of the Tiananmen Square massacre.

Tuesday will mark 30 years since the bloody event, which saw Chinese authorities brutally shut down long running student protests, killing thousands of people in and around the central square in Beijing.

Chinese Human Rights Defenders (CHRD), a US-based organisation for domestic and international activists, said the Beijing government’s “pre-emptive strikes” against anyone who might try to mark the anniversary had started in early May.

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“This year’s pre-June 4th crackdown continues a 30-year long campaign by the Chinese government to try to erase the memory and rewrite the history of the bloody military suppression of peaceful unarmed protesters and residents of Beijing and other cities on June 3-4, 1989,” said CHRD.

Human Rights Watch’s China researcher, Yaqiu Wang, said the rounding up of dissidents was pretty routine but while statistics weren’t available, there appeared to be an escalation this year. “It used to be that some activists would get harassed and intimidated, but this time people are being detained … and taken away by police,” she said.

“I feel there wasn’t a trigger for their detention, and it probably was related to the anniversary so I hope they can get released.”

According to human rights groups, Chinese authorities recently took activist Hu Jia on an enforced “guarded vacation” to a port city nearly 200 miles from his Beijing home, and put under house arrest or restricted the movement and communication of several members of the Tiananmen Mothers, including women in their 80s whose children were killed in 1989.

Facebook Twitter Pinterest Hu Jia, human rights activist Photograph: South China Morning Post/South China Morning Post via Getty Images

Founding member of the group, 82-year-old Ding Zilin, whose son was killed by troops in 1989, was forced to travel more than 600 miles to her home town in Jiangsu province on 20 May.

On 28 May several artists in Nanjing on a “national conscience exhibit tour” went missing and are feared to have been detained, according to Liu Lijiao, the wife of one artist, Zhui Hun.

The whitewash of Tiananmen and heightened repression across China Yaqiu Wang

On 16 May, CHRD, Human Rights Watch and media reports said police detained dissident protester Shen Liangqing in Anhui over “picking quarrels and provoking trouble” and did not inform his family for a week.

The following day an independent filmmaker, Deng Chuanbin, was detained after he tweeted a photo of a “Eight Liquor Six Four” bottle of alcohol, which references the massacre’s date, which is rendered in Chinese as 6/4.

The crackdowns come after a three and a half year jail sentence was handed down in April against activist Chen Bing, who was part of the group producing and selling the alcohol.

“Thirty years after the Tiananmen massacre, Chinese authorities have not acknowledged the atrocity or provided justice for the victims and their families,” said Wang.

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“The whitewash of Tiananmen and heightened repression across China have fuelled activists’ determination to fight for human rights.”

The Chinese government has shown no sign of softening its stance on the massacre, which has been largely erased from the nation’s official history.

The incident remains a key subject of China’s extraordinary and comprehensive censorship and surveillance system. More than 3,200 keywords are censored online in China, as well as thousands of photos – particularly those which show or mirror the famous “tank man” image. Hong Kong Free Press reported live streaming sites were also shutting down on Tuesday, ostensibly for “technical reasons”.

Australian China academic and author Louisa Lim said the cost of remembering the massacre had been escalating since Xi Jinping came to power. “This government is obsessed with control,” she said.

“He came to power in 2012 and every time a new leader comes in there’s a period where people think maybe it’s going to liberalise, maybe it’s going to change, but it doesn’t.”

Roseann Rife, east Asia research director of Amnesty, called on the government to allow people to commemorate the 1989 crackdown, and for an “open and independent” investigation into the incident. “Time is running out for the elderly parents whose children were murdered to see truth and justice.”