Cannot enter or leave the cities of Shijiazhuang and Xingtai, Hebei Province.
China has imposed restrictions on the 18 million inhabitants of these two towns located south of Beijing, in order to stem the upsurge in the number of cases the most serious in six months.
Highways, airports and train stations in these two cities are blocked, and schools are closed.
People in the areas closest to Beijing can only enter the capital upon presentation of a negative screening test within three days and proof of residence or work in Beijing.
Massive screening campaigns have been launched across the province.
The authorities plan to test all the inhabitants of these two municipalities.
Last week, Hebei reported 310 contaminations, most of which were detected in Shijiazhuang, the capital of Hebei.
A year ago, China announced the first official death from the coronavirus.
The country had succeeded last spring in stemming the epidemic which has since spread across the globe, killing nearly 1.9 million.
The country officially counted 4,634 dead, the last counted in May.