Police detained at least 11 Chinese activists after a pair of small events to commemorate the 28th anniversary of the bloody crackdown on pro-democracy protesters in Beijing's Tiananmen Square, according to human rights groups and activists.

Meanwhile, thousands gathered in Hong Kong for the annual candlelight vigil to remember the events of June 4, 1989, which have gained added poignancy in recent years in view of a continuing struggle for democracy there.

Tiananmen Square and the rest of Beijing are habitually placed under tight security for the anniversary, but activist Li Xiaoling apparently had her photograph taken at the square in the early hours of June 4. In it, she is holding up a sign bearing an image of her with a patch over her left eye, after an operation last month for injuries allegedly inflicted by police.

Li and fellow activists Li Zhou and Pu Yongzhu were taken to Xicheng police station in Beijing, Amnesty International and human rights activists said.

The sign reads: “Li Xiaoling from Zhuhai: tour of light on June 4th.”

Activists also commemorated the anniversary in Zhuzhou in southern Hunan province, taking photographs such as the one below, in which they form the Chinese characters for six and four, marking the sixth month and fourth day, the date of the crackdown.

At least eight members of the group have been taken away by police, while at least two are unreachable, according to activists and rights groups.

Police in Beijing's Xicheng district and in Zhuzhou did not respond to calls seeking information.

Tens of thousands of troops and tanks converged on Tiananmen Square to quash months of protests on the night of June 3-4, 1989. Several hundred people were killed — possibly several thousand — and more than 1,600 people nationwide were subsequently jailed. The final prisoner, Miao Deshun, a factory worker from Beijing, was released in October, with serious mental and physical health problems.

Despite those tiny protests, few young Chinese people appear to have much knowledge or even interest in the events of June 4, 1989, according to Louisa Lim, author of “The People's Republic of Amnesia: Tiananmen Revisited.” That has followed nearly three decades of propaganda and censorship by the Communist Party aimed at suppressing and rewriting history.

“Those who do know about it tend to be largely supportive of the crackdown, because they believe this prevailing view that the party did what was necessary to ensure stability and that stability has paved the way for the country's three decades of economic development,” she said.

“For young people, they see that their lives are better than their parents, and so they buy this narrative. It's a very black-and-white picture — chaos or stability — which precludes the possibility of any other outcome apart from repression, but these young people, whose ideas of what happened in 1989 are very sketchy and often completely incorrect, often have no reason to question it.”

William Nee, China researcher for Amnesty International, called on the Beijing government to come to grips with the crackdown and end the retaliation against anyone who dares mention the subject.

“Nearly three decades on, the families who lost children in the bloodshed continue to face surveillance and harassment, as the authorities continue to suppress their campaign for justice,” he wrote.  “Four activists face up to 15 years in prison after they were indicted in March this year, for 'inciting subversion of state power.' Their crime in the eyes of the authorities was to sell wine online with a label referencing June 4, 1989, and a picture of the iconic Tank Man.”

It is a very different story in Hong Kong, where tens of thousands gather every year to commemorate the crackdown. The self-governing territory had its own uprising for greater democracy in 2014, known as the Umbrella Movement, which failed to induce any concessions from the governments in Hong Kong or Beijing.

But there is tension in Hong Kong as another important anniversary approaches, the 20th anniversary of the territory's handover from British rule on July 1, with China looking to extend its political control over it and a small but growing cohort of citizens calling for outright independence from Chinese rule — while others maintain their demand for democracy for the territory within China.

“I came to the candlelight vigil not only for mourning, but also because I believe that with the situation in 1989 and the situation nowadays, we are also facing the same enemy and facing the same authoritarian regime,” Agnes Chow, a student leader involved in the 2014 protests, told CNN in Hong Kong's Victoria Park during the event.

An annual survey by the University of Hong Kong's Public Opinion Program found this year that 46 percent of the respondents believe that the Beijing students did the right thing in 1989, while 22 percent believe that they did the wrong thing. Meanwhile, just 12 percent supported the Chinese government's handling of the events of 1989, with 69 percent regarding it as wrong. Support for the students is higher among young people but has dwindled over the years.

There is also a small commemoration in the Taiwanese capital, Taipei, which started to move from martial law to democracy in the 1980s and held its first democratic presidential election in 1996. Its president, Tsai Ing-wen, said in a statement Sunday that the actions of the Chinese students and citizens in 1989 had “inspired a generation.”

The biggest gap between Taiwan and China is “democracy and freedom,” she said in a Facebook post and tweets, offering to help China follow the same path as Taiwan.

“Borrowing on Taiwan's experience, I believe that China can shorten the pain of democratic reform,” she said.

U.S. Secretary of State Rex Tillerson also marked the anniversary, with a call for China to make “a full accounting of those killed, detained, or missing” because of the events of June 4, 1989.

“We urge China to cease harassment of family members seeking redress and to release from prison those who have been jailed for striving to keep the memory of Tiananmen Square alive,” he said. “The United States views the protection of human rights as a fundamental duty of all countries, and we urge the Chinese government to respect the universal rights and fundamental freedoms of all its citizens.”