BEIJING (Reuters) - Apple Inc's AAPL.O online book and film services have gone dark in China, after Beijing introduced regulations in March imposing strict curbs on online publishing, particularly for foreign firms.

A female staff member assists a customer at an apple store in Beijing, November 2, 2015. REUTERS/Kim Kyung-Hoon

Attempts by Reuters on Friday to access Apple’s iBooks Store and iTunes Movies services were met with a message in Chinese saying they were “unusable”.

China’s media regulator, the State Administration of Press, Publication, Radio, Film and Television, demanded Apple halt the service, the New York Times reported, citing two unnamed people. The regulator did not respond to a faxed request from Reuters for comment.

“We hope to make books and movies available again to our customers in China as soon as possible,” said a Beijing-based Apple spokeswoman, who declined to provide further comment.

This is not the first time an Apple service has been made unavailable in China.

The company’s News app, launched last year, can be used in many countries by people who downloaded the app from the U.S., United Kingdom or Australia App Stores. But those people trying to access the service on the mainland are shown the message “News isn’t supported in your current region”.

The Apple spokeswoman in Beijing said News had only launched in the U.S., United Kingdom and Australia, but declined to comment on how the app could still be used in places like South Korea and Hong Kong but was blocked in mainland China.

Apple’s second-largest market by revenue is Greater China, which includes Taiwan and Hong Kong, driven by the iPhone’s popularity in the world’s biggest smartphone market.

But the company has at times met with official resistance from Beijing, with state media once branding the U.S. tech behemoth’s iPhone a danger to national security.

In March, regulations came into effect that prohibit foreign ownership and joint ventures in online publishing and stipulate that all content be stored on servers in China. The move sparked fear of greater curbs on foreign businesses.

In an effort to shape public opinion, President Xi Jinping’s government has implemented an unprecedented tightening of internet and media controls and sought to codify the policy within the law, a campaign that critics say ignores human rights and is a burden for business.

Earlier this month, the U.S. labeled China’s internet censorship a trade barrier in a report for the first time since 2013, saying worsening online restrictions are damaging the business of U.S. companies.

Officials say internet restrictions are needed to ensure security in the face of rising threats such as terrorism and foreign ideology that could destabilize China.