China’s cyber regulator is encouraging people to snitch on each other for online speech critical of the ruling Communist Party or its official historical narrative ahead of the 100th anniversary of its founding.

Members of the public can ring a new hotline to report people who defame the Party, Chinese leaders, government policies, national heroes or “deny the excellence of advanced socialist culture,” according to a notice posted by the Cyberspace Administration of China.

People online “with ulterior motives” were “maliciously distorting, denigrating and negating the history of the Party,” said the regulator, which has vowed to crack down ahead of the Party’s centennial birthday in July.