Chinese authorities have begun inquiries into some of the people who gathered at weekend protests against COVID-19 curbs, three people who were at the Beijing demonstrations told reporters, as police remained out in numbers on the city's streets.

In one case, a caller identifying as a police officer in the Chinese capital asked the protester to show up at a police station on Tuesday to deliver a written record of their activities on Sunday night.

In another, a student was contacted by their college and asked if they had been in the area where events took place and to provide a written account.