Users in China have already begun getting the message, said one former journalist who used to work in Beijing.

“I got this warning three times,” said Mei, who asked to be identified only by her first name for security reasons.

Concerned that the warning itself was an attempt to hack her account, she posted a question in a closed Google group, asking if anyone else got the message.

“So far about 10 of us have received the same message, some in Chinese, some in English,” she said. The group has about 200 members, she said.