Beijing – To the victor go the spoils. For China's ruling Communist Party on this 30th anniversary of the crackdown on pro-democracy protesters in Beijing's Tiananmen Square, those spoils have been the power to re-write history and erase memory. Anyone deviating from the official, cleaned-up narrative of the events of June 4, 1989 is met with a harsh reaction, including U.S. Secretary of State Mike Pompeo.

On Monday Pompeo honored "the heroes of the Chinese people who bravely stood up thirty years ago in Tiananmen Square to demand their rights." A statement issued by the Chinese Embassy in Washington D.C. slammed his remarks, calling them "an affront to the Chinese people," issued "out of prejudice and arrogance."

"Whoever attempt (sic) to patronize and bully the Chinese people in any name, or preach a 'clash of civilizations' to resist the trend of times will never succeed," the embassy's statement continued. "They will only end up in the ash heap of history."

A police vehicle is deployed in Tiananmen Square in Beijing, China, June 4, 2019. REUTERS

In Beijing, Foreign Ministry spokesman Geng Shuang echoed the embassy's sentiments on Tuesday, saying Pompeo's statement, "maliciously attacks China's political system, denigrates the state of China's human rights and religious affairs, wantonly criticises China's Xinjiang policy and severely interferes in China's domestic affairs."

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"These lunatic ravings and babbling nonsense will only end up in the trash can of history," Geng said.

China's sensitivity around the violent crackdown, the death toll and the eventual political course of the country have run high for three decades -- spiking each year at this time. An official death toll has never been published, but estimates range from a few hundred to a few thousand.

As for any official acknowledgement, China has rarely given more than a modicum. Earlier this week, speaking at a summit in Singapore Chinese Defense Secretary Feng Weihe only said Beijing's decision to break up the student-led protests of 1989 had been "correct."

The Chinese Embassy statement alluded even more vaguely to Tiananmen, insisting: "The Chinese government and people reached the verdict on the political incident of the late 1980s long ago."

On Tuesday, CBS News attempted to access Tiananmen Square at about 5 p.m. local time. We waited for an hour in a line along with about 150 other people, but were eventually turned away. Local Chinese citizens who wanted to enter the square today were made to scan their ID cards on a small white terminal before being ushered through a security checkpoint with metal detectors and then being allowed onto the square.

Chinese nationals and others line up at a security checkpoint to enter Beijing's Tiananmen Square on June 4, 2019, the 30th anniversary of Chinese security forces' deadly crackdown on pro-democracy protesters in the square. CBS

Your CBS News correspondent's passport and Chinese-issued press ID were taken as he was escorted to security team, which politely said he would need to apply for access with a ministry that had already closed for the day. On the walk back to the subway, two security guards followed until your correspondent was clear of the security area.

Erasing history

The Chinese government has largely succeeded in erasing Tiananmen from the nation's collective memory, relying on internet censors who continually monitor and wipe any reference from Chinese social media.

CBS News in Beijing found several examples.

On Twitter, an overseas Chinese user pointed out that he could not use the words "30 years ago" on Weibo, the country's own version of a Twitter-like platform, adding that he suspected some people in the country don't even know what happened at that time.

Other Chinese expatriates posted on Twitter about syncing delays on Weibo.

"Couldn't post weibo. Kept saying there's a syncing delay. I'm guessing they just temporarily blocked all the overseas IP," said one user.

One person tried to post "I remember," and received a notification from Weibo saying: "Your post was successful. For now the server has a delay with data syncing, please wait patiently, thank you very much."

Individual profile photos on Weibo could not be changed. In the past, images of candles -- and Winnie the Pooh, who some people believe resembles Chinese President Xi Jinping -- have been banned on the platform.

While virtual private network (VPN) programs enable internet users in China to burrow through the "Great Firewall" to access Western news sites and social media like Twitter and Facebook, such sites have also been hit in China with palpably slower download speeds.

Hong Kong stands apart

While mainland China will see no public commemorations of the Tiananmen crackdown, a limited degree of autonomy on the island of Hong Kong -- still Chinese soil -- will allow for the annual candlelight vigil to go ahead as planned.

The special administrative region and former British colony has held a massive vigil every year since 1989.

According to the Hong Kong-based South China Morning Post newspaper, organizers expect this year's turnout to match a record last hit on the 25th anniversary in 2014. That year about 180,000 people were estimated to have attended.

Tens of thousands of people participate in a candlelight vigil at Hong Kong's Victoria Park June 4, 2014, to mark the 25th anniversary of the military crackdown of the pro-democracy movement at Beijing's Tiananmen Square in 1989. REUTERS

Turnout has varied since then, but it is seen as a barometer of local frustration with the Hong Kong local government as much as it is with the central leadership in China. It is a rare opportunity for Chinese nationals to voice their hopes for democracy, and their calls for Beijing to own its past.

CBS News' Grace Qi contributed to this report.