Amazon.com Inc's cloud-computing customers in China are being told not to use software to bypass China's internet gates, under a government clampdown.

Amazon Web Services' Chinese partner, Beijing Sinnet Technology Co Ltd, sent out emails asking users to delete tools that allowed them to bypass the country's vast system of internet filters. Tools used by clients include virtual private networks, or VPNs.

"Sinnet is responsible for ensuring that its customers in China comply with local laws and their notice was intended to remind customers of their obligations," an Amazon spokeswoman said via email.

Sinnet's demands have been prompted by requests from China's public security ministry and Ministry of Industry and Information Technology. According to a person familiar with the matter, there was no change in the way Amazon's services worked in China, Fox News reported.

On Saturday, Apple pulled out software from its app store in China that allowed users to get around the country's web filters. The Cupertino, California, technology company cited new rules requiring providers of VPNs, to obtain licenses from regulators.

Complaints of disruptions affecting users of overseas VPNs in China have increased manifold recently. Facebook Inc 's encrypted WhatsApp messaging service has also been affected as users reported difficulty in sending messages.

Amazon had a run in with the Chinese authorities earlier due a to microblog app called FreeWeibo, that allowed users to access posts deleted by censors on the Chinese social network Sina Weibo.

According to commentators, the clampdown this time seemed to be getting harder.

''If users don't comply with the guidance, the offered services and their websites can be shut down. We the operators also check routinely if any of our users use these softwares or store illegal content,'' a Sinnet hotline service operator with the surname Wang, told the New York Times on Monday.