BEIJING, (Reuters) – Central Chinese cities Yuzhou and Zhengzhou imposed travel restrictions after sporadic COVID-19 case. This was in accordance with a national strategy which has become more urgent due to the Winter Olympics as well as the Lunar New Year holidays.

Yuzhou, a city located in Henan’s central province, has asked its 1 million inhabitants to not leave the area since Jan. 2. However the number of cases for Yuzhou and the whole province is still very small. Henan recorded four cases of domestically transmitted disease and 18 local asymptomatic illnesses on Tuesday.

China demands officials to act quickly in order to stop clusters of infection.

Yuzhou’s residents were limited to sending one individual to purchase daily necessities at specified venues each two days. In high-risk areas, people were instructed to stay at home and depend on deliveries.

Authorities warned the public that COVID-19 was a serious problem in their city. The source of the virus is still not known. They demanded that government officials prioritize virus control.

Authorities said the case number in Xian, a northern city of 13,000,000, was falling after it has been locked down for more than two weeks. According to official data, there were 35 cases of local symptoms on Tuesday. This is a marked decrease from the 95 reported a day prior and the 150 per day recorded during Dec. 25-31.

A Wednesday document by the Xian City government showing concrete plans to relax or end residential compound lockdowns, was passed on Wednesday to residents of the city through local online chat groups.

Depending upon the number of cases or close contacts in each district or within specific residential communities, there are different restrictions. While some are prohibited from moving out of their apartments, others can move downstairs within the residential complexes. Others may travel further.

A city official stated Wednesday that more than 42,000 people were currently in Xian’s central COVID-19 quarantine facility as of Tuesday.

State television reports that Zhengzhou is the capital city of Henan province. Residents in dangerous areas were advised not to leave without COVID-19 approval. Other residents were warned not to travel out of Zhengzhou, unless absolutely necessary.

A government statement stated that the overall virus situation at Zhengzhou is under control. It is currently conducting an extensive test of its 12.6million residents.

There were also two counties within Henan that fell under Zhoukou and Luoyang cities’ jurisdictions.

Two local cases of symptomatic infection were reported in Zhejiang, eastern China on Tuesday. Four local asymptomatic cases were reported by Shanghai.

As of the beginning of Jan. 4, there were 102,932 confirmed symptomatic instances in China. These included both locally-sourced and imported cases.

No new deaths were reported for Tuesday. The death total remains unchanged at 4,636.