A Chinese newspaper says a man has been detained after he altered an image of the paper's front page to add a headline declaring the official adoption of a "two-wife" policy, a joke on the country's new "two-child" policy.

Yangjiang Daily, a state-owned newspaper in the southern Guangdong province, said Friday that the altered image spread quickly on social media, causing an "ill impact."

Chinese authorities have been cracking down on rumors and false information circulating online, saying they disrupt the proper flow of information on the Internet.

Yangjiang Daily said the man, identified only by his family name, Lin, altered the image of the newspaper as a joke with colleagues but that it was shared online.

The original headline was about the opening of a city meeting.