BEIJING, Jan. 9 (Xinhua) -- China's health authority on Friday called for strengthened measures to curb COVID-19's recent spread in north China's Hebei Province.

Citywide nucleic acid testing should be carried out fast with quality, said Ma Xiaowei, head of the National Health Commission. He made the comments during a video conference on the epidemic prevention and control work of Hebei.

Potential infection sources should be identified promptly through epidemiological investigations, Ma said, urging improved coordination among various departments to find transmission chains as soon as possible.

Ma stressed that enough rooms should be prepared for quarantine, calling for better medical worker training and other measures to prevent nosocomial infections.

By Thursday, about 3,000 medical workers have arrived in Shijiazhuang, the capital city of Hebei, to support the city's prevention and control of COVID-19.