Apple is taking steps to remove a malicious program found in a number of applications used by owners of iPhones and iPads in China, in possibly the first large-scale attack on Apple's App Store. Apple said hackers had embedded a malicious code into the apps by persuading developers to use a counterfeit version of the firm's own software. The program called XcodeGhost allows hackers to collect data from devices.

The infected applications include many used by iPhone and iPad owners in China such as the hugely popular WeChat app, a music downloading app and a car hailing app.

Apple said the apps had now been removed.

On its official WeChat blog, Tencent said that the security issue affects an older version of the app - WeChat 6.2.5 and the newer versions were not impacted.

It is the first reported case of large numbers of malicious software programs making their way past Apple's stringent app review process. Prior to this attack, only five malicious apps had ever been found in the App Store,

According to cyber security firm Palo Alto Networks Inc., the malware had limited functionality.

Chinese security firm Qihoo360 Technology also said on its blog that it had uncovered 344 apps tainted with XcodeGhost.