Apple store users cannot find Amazon's audiobook service Audible and several other phone apps used for reading the holy books of Islam and Christianity on the platform in mainland China. This is the latest example of the impact the country's tightened rules for internet firms have had on services. Audible removed its app from the Apple store in mainland China last month "due to permit requirements," the company said on Friday. Unlike LinkedIn, which has been offering a specialized Chinese service since 2014, Amazon-owned Audible said it does not have a dedicated service for customers in China. The makers of apps for reading and listening to the Quran and Bible have said that Beijing got their apps off from Apple's China-based store. Apple has so far not commented on the issue. The Chinese embassy in the US said that the Chinese government has "always encouraged and supported the development of the Internet" but refused to comment further, according to the Associated Press. The statement said that the development of the internet must obey Chinese laws. Though China's government has tight control on the internet in the country already, it is increasingly stepping up its enforcement of the internet sector in other ways. Chinese regulators this year have sought to strengthen data privacy restrictions and went on to limit how much time children can play video games. They are also exerting greater control over the algorithms used by tech firms to personalize and recommend content. The popular US language-learning app Duolingo disappeared from Apple's China store over the summer, as have many video game apps. What appears to link Audible with the religious apps is that all were recently notified of permit requirements for published content. Pakistan Data Management Services, which makes the Quran Majeed app, said it is awaiting more information from China's internet authority about how it can be restored. The app has nearly 1 million users in China and about 40 million worldwide, said the Karachi-based company. Those who had already downloaded the app can still use it, said Hasan Shafiq Ahmed, the company's head of growth and relationships. The maker of a Bible app said it removed it from the Apple store in China after learning from Apple's App Store review process that it needed special permission to distribute an app with "book or magazine content." Olive Tree Bible Software, based in Spokane, Washington, said it's now reviewing the requirements to obtain the necessary permit "with the hope that we can restore our app to China's App Store and continue to distribute the Bible worldwide." The removals were first detected this week by watchdog website AppleCensorship, which monitors Apple's app store to detect when apps have been blocked, especially in China and other countries with authoritarian governments. (With AP inputs)