BEIJING (Reuters) -China’s northeastern city of Harbin, population 10 million, went into semi-shutdown after reporting new locally transmitted COVID-19 cases for the first time since early February.

The National Health Commission (NHC), Wednesday said that three of the 16 newly reported local cases in China on Sept. 21 were found in Harbin. This is the capital city of Heilongjiang. On February 4, the last locally transmitted case was reported in Harbin.

Harbin is known for its cold winters of minus 30 degrees Celsius (minus 22 Fahrenheit). On Wednesday, Harbin pledged to finish the initial round citywide testing before Thursday. Residents were asked to stay inside their homes until their results are available.

It has instructed its citizens to stay in the city unless they have an urgent reason, and anyone who does leave should produce evidence of any negative tests within 48 hours.

According to state television, indoor facilities such as gyms, cinemas, and mahjong parlours were shut down. Also, tourist sites were told to keep their visitor numbers at half the capacity.

Late Tuesday night, the state television announced that all classes in kindergartens, primary schools, and high school will be suspended offline for one week.

The cause of the new Harbin cases was not immediately clear.

One of the new cases was reported to have been discovered by state TV. The person visited a local hospital in order to undergo testing.

Two of the other close relatives of the first victim returned from the Philippines in August. They were quarantined first in Guangzhou, then moved to Harbin.

Bayan, the county where three of these cases resided, has suspended taxi and bus services as well as locked down certain areas.

According to NHC, 13 cases were reported in Fujian by Xiamen, Putian, and Putian for September 21, a decrease from last week’s average daily count.

Sun Chunlan, vice premier of Fujian, stated Monday that it was not advisable to be optimistic about Fujian’s progress. There are uncertainties still and there is no way out. State media also reported that Sun Chunlan cautioned officials against being too positive.

According to Fujian Daily, Sun called for stricter efforts to secure communities at risk from the virus.

All four Fujian cities (Xiamen Quanzhou Zhangzhou and Putian) that reported cases of local illness have told residents to stay put unless there are urgent reasons.

The authorities have closed down high-risk areas, shut down public places, stopped long-distance bus service, and stopped offline education at primary and secondary schools, kindergartens and high schools.

Zhangzhou asked local authorities for tighter approvals to allow foreigners to enter the area.