BEIJING- Google services are being disrupted in China ahead of this week's 25th anniversary of the 1989 crackdown on pro-democracy demonstrators around Beijing's Tiananmen Square, a censorship watchdog said today.

GreatFire.org said in a blog post that the government appeared to have begun targeting Google Inc's main search engine and Gmail, among many other services, since at least last week, making them inaccessible to many users in China.

It added that the last time it monitored such a block was in 2012, when it only lasted 12 hours.

"It is not clear that the block is a temporary measure around the anniversary or a permanent block. But because the block has lasted for four days, it's more likely that Google will be severely disrupted and barely usable from now on," the advocacy group said.

Asked about the disruptions, a Google spokesman said: "We've checked extensively and there's nothing wrong on our end."

Google in 2010 moved its Chinese search engine service out of China, the world's second-largest economy, citing rampant censorship, and now operates it from Hong Kong.

The Chinese government already blocks the popular foreign websites Facebook, Twitter and Google's own YouTube.