In Urumqi, the new outbreak is associated with a cluster of group activities and has developed at a relatively fast pace, Rui Baoling, head of the city's disease control and prevention center, said over the weekend.

Most of the 30 confirmed patients as of Saturday had mild or moderate cases, and a total of 41 asymptomatic patients and 2,705 close contacts were in isolation for medical observation, according to Rui.

She said the majority of newly confirmed and asymptomatic cases were detected in Tianshan district and they were all already placed under quarantine, so there was no need to panic.

Zhang Wei, head of Urumqi's health commission, said that the city was carrying out a citywide, free testing campaign beginning in neighborhoods that have reported new cases and among close contacts or residents with a fever, and it would gradually extend across the entire city.

Twenty-five certified testing institutions and over 1,600 medical workers will be conducting the tests.