BEIJING (Reuters) - China ordered its journalists on Saturday to learn "Marxist news values" and uphold the principles of news as prescribed by the ruling Communist Party, the latest step in President Xi Jinping's crackdown on the media.

The guidelines by the All China Journalists' Association, published by state news agency Xinhua, are aimed at both traditional and online media and are another sign of Xi's politically conservative agenda.

The association said journalists "must learn to master Marxist news values".

"Let us hold high the banner of socialist core values," the report said, using the party's term for orthodox beliefs.

Xi has espoused old school Maoism as he seeks to court powerful conservative elements in the party. Like many officials before him, Xi is steeped in the party's long-held belief that loosening control too quickly or even at all could lead to chaos and the break up of the country.

In July, the State Administration of Press, Publication, Radio, Film and Television said China would toughen curbs on journalists disclosing state and commercial secrets.

Early this year, Chinese journalists also had to pass a new ideology exam to keep their press cards. They were required to do a minimum 18 hours of training on topics including Marxist news values and Socialism with Chinese Characteristics.

Chinese state media has traditionally been the main vehicle for party propaganda. Reforms over the past decade that have allowed greater media commercialization and limited increases in editorial independence, combined with the rise of social media, have weakened government control slightly.

(Reporting by Sui-Lee Wee; Editing by Paul Tait)