The Chinese government cut off access to Google search, Gmail, Google Calendar and more of the company's services ahead of the 25th anniversary of the Tiananmen Square protests.

Google has been largely inaccessible to Chinese citizens for about four days now as the government attempts to choke off any discussion of pro-democracy protests that took place in 1989 and resulted in a government crackdown that killed up to several thousand people. (An official death toll was never released.)

According to the New York Times, the blockage affects about 90% of Chinese users, just enough for the government to claim that the problems are on Google's end, though the company says otherwise.

"We’ve checked extensively, and there are no technical problems on our side," a Google spokesperson told Mashable. The company's real-time traffic report also shows a steady decline in China's activity after May 30.

Facebook, Twitter and YouTube, which is owned by Google, are already inaccessible throughout China, and Google's search results there are regularly censored.

A sanitation worker cleans Tiananmen Square after it was occupied by protesters on May 26, 1989. Image: Jeff Widener/Associated Press

But this attempt to block the company's services is the most extensive since a 12-hour period in 2012, according to GreatFire.org, a website that monitors Internet censorship. Even international versions of Google, such as Google Australia, are inaccessible to most people in China right now.

“We’ve certainly seen all these pathologies on display—from censorship to detaining known government critics every year—but they have been significantly worse this year," Sophie Richardson, China director at Human Rights Watch, told Mashable.

The Chinese government has moved swiftly to erase any online references to the increased censorship over the last few days. Posts complaining of a dysfunctional Google Calendar on China's microblogging website, Sina Weibo, have been quickly wiped away.

Beijing has also been quick to cut off discussion of the Tiananmen Square protests in public. Officials have reportedly detained and even arrested people who have attempted to memorialize the events of 1989 in recent days.

“In general what we’ve seen is the [Chinese President] Xi Jinping government has taken a harsher stance toward civil society and human rights than some of his predecessors," William Nee, China researcher at Amnesty International, told Mashable. "Perhaps he’s using this as a little bit of a way to redraw the red lines on what is acceptable and what is not."

Nee hopes detainees will be released after June 4, when the anniversary has passed, and that censorship levels will also return to normal. But he's far from sure that will happen.

“I think it will be interesting, in the coming weeks, to see how much this will become the new standard," he said.

In the meantime, GreatFire.org has built a website that mirrors Google's capabilities. It's hosted on the cloud, which is used by many national companies, meaning Chinese authorities would risk damaging business interests if they were to take it down.