Facebook’s WhatsApp messaging service has been partially blocked in China, following a censorship crackdown by the government, Bloomberg reports. Multiple WhatsApp users in China reported experiencing intermittent outages from Monday night Beijing time. By Tuesday morning, users had taken to social networks such as Twitter to report that photos as well as audio clips, were not being delivered. WhatsApp is not responsible for the blockage, according to a person familiar with the matter. The company declined to comment. While WhatsApp messages are encrypted, WeChat is unencrypted and highly censored, Smith said. On WeChat, a hugely popular messaging app run by China’s Tencent, people are asked to use their real names. “This is part of the censorship master plan,” Smith said. Chinese authorities have been ramping up censorship of social media and messaging platforms as the government prepares for the 19th Communist Party Congress.