Latest updates on COVID-19 outbreak in Hebei province: 

A lockdown has been imposed on Hebei's capital city Shijiazhuang. 

Vehicles are not allowed to enter or exit Shijiazhuang, the provincial capital. 

Many flights to and from Shijiazhuang have been canceled, railway station closed to passengers leaving the city.

51 new confirmed cases and 69 asymptomatic carriers are reported in Hebei on Thursday. 

Vehicles are not allowed to enter or exit all areas administrated by Shijiazhuang, except for those transporting materials or necessities for the city's fight against the current outbreak, according to a notice released on Jan 7 by the city's anti-virus working group. 

Vehicles carrying materials for medical use, life essentials and production are allowed to enter or leave the city with a certificate issued by related authorities, the notice said.

Each vehicle can only have two persons, who need to be checked for ID cards and negative nucleic acid test results.

Vehicles for public affairs like military or police cars, firefighting vehicles and ambulances are not limited if passengers have normal temperatures.

Shijiazhuang has become the epicenter of a new round of COVID-19 in China, with 83 confirmed cases as of Thursday that have all emerged since the weekend.

Shijiazhuang has suspended more major transport links with outside places to lower infection risks as the city reported the biggest rise in daily COVID-19 cases since the new outbreak occurred at the weekend.

It reported 50 new locally transmitted cases on Thursday, among 51 in Hebei, and 52 in the Chinese mainland.

Many flights to and from Shijiazhuang have been canceled since Thursday morning, according to authorities in Shijiazhuang Zhengding International Airport.

The airport is less than 10 kilometers away from Gaocheng district, the only high-risk area for infection in Chinese mainland. Most cases in Shijiazhuang are centered in the district.

Shijiazhuang Railway Station, the biggest station in the city, has stopped passengers from taking trains to leave, according to a notice by the city's security bureau.

Train tickets departing Shijiazhuang were also stopped earlier. Tickets can be refunded without extra fees charged.

Xingtai, another city in Hebei, which also has reported confirmed cases in recent days, suspended six buses on Thursday. It already stopped 20 buses on Wednesday, according to the city's public transport company.

Before Thursday, cross-city buses, shuttle buses between the airport to its downtown center and neighboring areas, as well as expressways had been suspended.

Hebei reported 51 confirmed COVID-19 cases and 69 asymptomatic carriers on Thursday, all locally transmitted, bringing its total of recently confirmed cases to 90 and local asymptomatic carriers to 144, according to the Health Commission of Hebei.

Three officials in Shijiazhuang's Gaocheng district, which is the epicenter of the latest outbreak in China, have been punished for negligence in COVID-19 intervention, said the city's top anti-corruption authority.

"Villages should identify, report, isolate and treat cases as early as possible, so as to cut off the transmission," Wu Hao, an expert at the National Health Commission's Advisory Committee for Disease Control and Prevention, said in a news report by cnr.cn.

Compared with cities, villages are more vulnerable to outbreaks, because the medical conditions there are not as good, publicity is limited and there are more elderly people and children, whose health awareness is relatively low, he added.

To lower the risk of virus spread, all communities and villages in Shijiazhuang, the provincial capital, have been under closed-off management since Wednesday morning.

The city has also suspended major transport links with outside areas, including long-distance buses and expressways and banned gatherings. People are urged to cancel or delay weddings. Passengers taking trains or flights must have a negative nucleic acid test result within three days of departure.

Citywide testing for all 10.39 million residents in Shijiazhuang started on Wednesday. 

The provincial health commission in Hebei has sent about 1,000 medical workers from other cities to Shijiazhuang as of Wednesday to support its fight against the outbreak, Zhang Dongsheng, deputy head of the Shijiazhuang health commission, said at a news conference on Wednesday, adding that another 2,000 medical workers will arrive in the city on Thursday.