BEIJING -- LinkedIn is launching a Chinese-language site for the most populous Internet market and says it will comply with the communist government's censorship rules.

The professional networking service will compete with established Chinese-language services Tianji, owned by France's Viadeo SA, and homegrown rivals Ruolin and Dajie. LinkedIn says it has 4 million users in China but until now its service was in English.

Professional networking services see fast-developing economies such as China and India as important sources of growth. In China, LinkedIn says it sees a potential market of 140 million professionals. Unlike Facebook, Twitter and other sites, LinkedIn has always been allowed to operate in China.

LinkedIn Corp., headquartered in Mountain View, California, acknowledged that expanding in China raises "difficult questions" because it will be required to censor content.

Such restrictions have hampered some other Internet services. Google Inc. closed its mainland search engine in 2010 after a dispute over censorship. Chinese authorities block access to Twitter and Facebook.

LinkedIn promised to make clear how it conducts business in China and to undertake "extensive measures" to protect members' rights and data.

"Government restrictions on content will be implemented only when and to the extent required," said CEO Jeff Weiner in a statement. "LinkedIn will be transparent about how it conducts business in China and will use multiple avenues to notify members about our practices."

Two-thirds of LinkedIn's 277 million users are outside of the U.S.

China had 618 million Internet users as of the end of 2013, according to an industry group, the China Internet Network Information Center.