BEIJING — This is not a joke. Chinese citizens who'd like to lay some harmless April Fools' Day pranks are hereby warned: "This is illegal." Such is the official message published by Xinhua Viewpoint, the Chinese government's microblogging account.

"April Fool's Day does not conform to our country's cultural traditions and core socialist values. We hope that the public do not believe in rumors, do not spread rumors, and do not pass on rumors." noted the Xinhua Viewpoint Friday morning, with a caricature showing two mobile phones titled "illegal" with a man's hand pointing to two other bubbles reading "Forward" and "Rumor."

Naturally, in the surprisingly freewheeling space of Chinese social media, there was plenty of fun to have with the official line. "This is the most profound April Fool Day's joke," said one blogger.

Another concurred, with a nod to the "humor" of the evening news broadcast: "We don't need this celebration since we Chinese can have the fun every evening at 6 p.m."

Apart from posting the illustration and the note of warning, the Xinhua also published a commentary piece saying that April Fool Day interests only "a very small minority" of the public, and that "Chinese people generally have a more serious attitude towards festivals and celebrations which are rarely pure entertainment."