The city of Heihe in Northeast China's Heilongjiang province reported a confirmed case and an asymptomatic case of COVID-19, both locally transmitted on Tuesday, according to the city's Center for Disease Control and Prevention.
Heihe, a port city on the China-Russia border, has conducted city-wide coronavirus tests for all residents, local officials said at a news conference held on Tuesday afternoon.
The confirmed case, a 73-year-old female resident surnamed Zhang, tested positive for coronavirus on Monday when she sought medical treatment at the Heihe Second People's Hospital outpatient clinic.
Then she was diagnosed as a confirmed case in severe condition.
The asymptomatic case, surnamed Zhao, an 18-year-old senior at a senior high school, is Zhang's granddaughter and lives with Zhang.
The Xuefujiayuan residential community where the two patients live was classified as a medium-risk area for COVID-19 starting on Tuesday at noon.
According to the emergency plan for COVID-19 prevention and control, the city has carried out a series of measures, including epidemiological investigation, city-wide nucleic acid testing, close contacts quarantine and comprehensive disinfection.
Airport and railway services for passengers were suspended, according to notices from the Heihe Railway Station and Heihe Aihui Airport.