Even though the ongoing COVID-19 outbreak in Hebei province is spreading relatively fast and hasn't reached its peak yet, it's still containable, a senior expert said on Friday.

As of 10 am Friday, Hebei had confirmed 127 COVID-19 cases and detected 183 asymptomatic carriers since Jan 2, Xu Jianpei, vice-governor of Hebei, said at the first provincial-level news conference for epidemic control.

A total of five patients had severe symptoms but are in stable condition, according to Tong Zhaohui, an expert with the National Health Commission.

All are under close observation for potential acute symptoms that usually appear after seven to 10 days of the onset of the disease, he added.

To curb the virus spreading, the two cities of Shijiazhuang and Xingtai, where the outbreak is centered, have been carrying out citywide nucleic acid tests since Wednesday and both promised to finish testing all samples by Saturday. A total of 10 medical teams from Jiangsu and Zhejiang provinces arrived in Hebei to help.

By midday Friday, Shijiazhuang had collected over 9.8 million samples for nucleic acid tests, over 6.2 million of which have been tested, Meng Xianghong, vice-mayor of Shijiazhuang, said on Friday night.

Some samples will be sent to other places for testing, including Beijing, Tianjin and Shandong province. The tests will be completed on Saturday, she said.

Gaocheng district in Shijiazhuang, the only high-risk area in the country, has finished sample collection and tested over 500,000 samples, among which 259 had positive results as of midday Friday.

By 3 pm on Friday, Xingtai had collected over 6.6 million samples, accounting for more than 94 percent of its population, and tested over 3 million, among which 15 showed positive results, all in the city of Nangong, according to a news conference in Xingtai on Friday.

To encourage compliance, Nangong officials said they would reward anyone who reported people who are proved to not have taken the test. Some other places in Shijiazhuang have rolled out similar measures.

Two hospitals in Shijiazhuang and one in Xingtai have been cleared exclusively for COVID-19 patients, according to the provincial news conference.

Case studies showed most of the cases are from villages close to an airport, said Wu Hao, an expert at the National Health Commission's Advisory Committee for disease control and prevention.

Also, many, as Wu said, had recently attended gatherings such as weddings, funerals and conferences before contracting COVID-19.

According to a recent study published in China CDC Weekly, the first case detected in Shijiazhuang on Jan 2, a 61-year-old woman, had a history of visiting family and attending religious gatherings in the village, with sporadic mask wearing.

To further strengthen disease intervention in the capital, Beijing announced on Friday that all 155 places for religious activities would be closed temporarily and religious events suspended.

Starting on Friday, Beijing Daxing International Airport suspended service at its Gu'an terminal, which is located in Gu'an county, Hebei province. Passengers need to go to the airport's terminal in Daxing in Beijing to check in. Shuttle buses between Daxing and all other cities outside of the capital have been suspended.

Liaoning province reported two new locally transmitted cases on Friday, while Beijing and Heilongjiang province reported one each, according to the National Health Commission.