Google Inc said several of its online services have been blocked in China.
Traffic to Google's services in China dropped sharply beginning Friday evening there, according to an online "Transparency Report" website operated by Google, which provides updates about access to its services in different parts of the world.
Among the sites affected were Google's search engine and its Gmail web email product.
The disruptions come as China's once-in-a-decade meeting to appoint new leadership gets underway.
A Google spokeswoman said the company did not know why the disruption was happening. Google said in a statement that it had "checked and there's nothing wrong on our end."
Google's YouTube video service has been inaccessible in China since 2009, while access to other services in China are blocked sporadically.
In 2010 Google relocated its Chinese search engine to Hong Kong after a spat with authorities over censorship and cyber-attacks that Google said originated in China.