SAN FRANCISCO (BLOOMBERG) - Apple came under fire on Monday (Oct 14) for sending web browsing data, including IP addresses, to China's Tencent Holdings, the latest criticism of how the company operates in the world's most populous nation.

Apple sends data to Tencent as part of an iPhone and iPad security feature that warns users if a website is malicious or unsafe before they load it.

The US company checks addresses against an existing list of sites known to be problematic. That list is maintained by Tencent for users in mainland China and by Google for other regions, including in the US.

In newer versions of Apple's iOS operating systems, the company says this feature "may also log your IP address," potentially providing Tencent, a Chinese conglomerate with government ties, data such as a user's location.

"We deserve to be informed about this kind of change and to make choices about it," Matthew Green, a cryptographer and professor at Johns Hopkins University, wrote in a recent blog.

"Users should learn about these changes before Apple pushes the feature into production, and thus asks millions of their customers to trust them."

Apple said in a statement that the feature protects user privacy and safeguards people's data.

The checks occur on the devices, and the actual web addresses are never shared with Tencent and Google, the safe browsing providers.

The feature is on by default, but can be switched off, Apple also said.

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The issue has come to light at a time when Apple is being scrutinised for appeasing China.

BuzzFeed recently reported that Apple told creators of shows for its TV+ streaming service to avoid portraying China in a poor light.

The company recently removed the Taiwanese flag from the emoji keyboard on devices running in Hong Kong and Macau, after earlier pulling it from mainland China.

It also came under fire for removing a maps app in Hong Kong that the developer said was designed to help users avoid areas of protest.

Apple said it was following local laws in both instances.