People in China who attended weekend protests against Covid restrictions say they have been contacted by police, as authorities begin clamping down.
Several people in Beijing said police had called demanding information about their whereabouts.
It is unclear how police might have discovered their identities.
On Tuesday officials renewed a promise to speed up efforts to vaccinate older people. Vaccination rates among elderly people are relatively low.
China has recorded record numbers of new cases in recent days.
Over the weekend, thousands in China took to the streets demanding an end to Covid lockdowns – with some even making rare calls for President Xi Jinping to stand down.
But on Monday, planned protests in Beijing did not happen after officers surrounded the assembly point. In Shanghai, large barriers were erected along the main protest route and police made several arrests.
