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

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 blocking action was in 2012, when it only lasted 12 hours.