Shanghai ordered its residents over the weekend to avoid all but essential travel in or out of the city and halted long-haul bus services on Sunday, as a coronavirus outbreak continued to spread in the metropolis and across much of mainland China.

While China still has far fewer COVID-19 cases than most countries, the daily count of infections has accelerated rapidly. The country’s National Health Commission reported 3,122 new cases on Sunday, up from 1,524 on Saturday and 1,100 on Friday, and a couple of hundred per day just a week ago.

The most severe outbreaks are in towns and cities in the northeastern province of Jilin, which accounted for two-thirds of the cases announced on Sunday. Two mayors were dismissed in the province on Saturday, in hard-hit Jilin City and in the Jiutai district of the city of Changchun.