The all-encompassing mission — announced Monday and paid for by district governments — contrasts with shortages of testing kits in some other countries, including the United States, where people have complained about not being able to get a test despite having coronavirus symptoms.

But the scope of the endeavor underscores official sensitivities about any new flare-up in Wuhan, where the virus emerged in a market late last year. It comes after officials reported six new coronavirus cases in two days, confounding health experts after a 35-day streak without infections.

“It is important to realize that a decisive result does not equal a decisive victory, lowering the emergency response level does not equal lowering defenses,” said Wang Zhonglin, a top official in the Communist Party in Wuhan, according to the state-run Changjiang Daily. “We must not be careless or lax,” he told a video conference of officials called to respond to a sudden spate of cases in the city.