China on Wednesday started blocking the online storage service Dropbox.
Censorship watchdog group GreatFire.org reported the blocking on Thursday, stating that access had been cut to dropbox.com and to the company's apps.
China had previously tried blocking Dropbox as far back as 2010, GreatFire.org said in an email. But in early 2014, Dropbox updated its app to use the HTTPS (Hypertext Transfer Protocol Secure) communications protocol, helping it bypass the country's censorship.
China, however, has begun cutting access to Dropbox's HTTPS address, banning the company's services completely in what GreatFire.org said was the "strictest method of blocking."
Dropbox did not immediately respond to a request for comment. The Dropbox site was inaccessible from Beijing, and the company's apps failed to synch data between devices.
China has been stepping up its censorship lately, targeting Google on May 31 with a block that's disrupted access to nearly all the company's services. The government has given no explanation for the move, but it took place just ahead of the 25th anniversary of the Tiananmen Square pro-democracy protests that were brutally quashed on June 4, 1989.
The historical event is among the many censored topics in the country; before it was blocked, Google was one source of unfiltered search results about it.
Prior to the Google block, terrorists in China's western Xinjiang region also killed dozens in a bombing attack. The country's state-run media later reported that Chinese police had arrested several terrorist groups that had been using messaging apps and online videos to organize.
In the case of Dropbox, the service's blocking will probably affect few users. China's own Internet giants including Baidu are offering similar cloud storage services and Dropbox has yet to actively market its services to the country.
In recent weeks, Chinese Internet users have been complaining about the country's Google blocking, and have urged the government to end it. Government censors, however, are deleting social-networking posts about the topic, according to GreatFire.org. The group is cataloging the deleted posts on one of its sites.