Shijiazhuang in Hebei province has in recent days stepped up its fight against a COVID-19 outbreak. By Thursday, Hebei reported 523 confirmed locally transmitted cases and 320 asymptomatic cases since Jan 2. Medical workers from other parts of China have been sent to Hebei to offer front-line assistance, while thousands of prefabricated rooms were being constructed in the city's Gaocheng district, a high-risk area of infection. By Wednesday, more than 5,400 residents from the worst-hit villages in Gaocheng had been transferred to centralized quarantine facilities, local authorities said.