A medical worker wearing a protective suit collects a throat swab from a local resident for Covid-19 antigen rapid test at a temporary testing center on Jan. 6, 2021 in Shijiazhuang, Hebei Province of China.Visual China Group | Getty ImagesBEIJING — Chinese authorities are starting to lock down parts of a province neighboring Beijing after a spike in coronavirus cases.The restrictions implemented in Hebei this week are some of the strictest since the spread of Covid-19 stalled within the country in March, and come as new waves of the coronavirus hit the U.S. and Europe. China’s initial tough response to the pandemic contributed to a 6.8% contraction in the economy in the first quarter.Shijiazhuang, the capital of Hebei province and located about a three-and-a-half hour drive southwest of Beijing, reported 50 new confirmed coronavirus cases and 67 asymptomatic ones for Wednesday. It brought the provincial total to 90 current confirmed cases and 144 asymptomatic cases.The city has stopped passengers from going to its train station, suspended long-distance buses, closed schools and put tighter control on entering apartment compounds, while authorities have blocked major highways in the province, according to state media.Hebei province began to disclose a few coronavirus cases over the weekend, with state media attributing some to wedding attendees.The new cases come a few weeks after Beijing reported a handful of cases in close succession, prompting mass testing in certain districts of the nation’s capital city.Chinese authorities have touted their ability to control the virus ahead of the developed world, and blamed most of the cases since last spring on foreign sources. The country is the only major economy expected to have grown in 2020.But late last year, officials began to express more concerns about the ongoing pandemic.The increase in coronavirus cases in the latest Hebei outbreak indicates the virus has spread for a period of time, Feng Zijian, deputy head of the Chinese Center for Disease Control and Prevention, said in an interview with state media earlier in the week.Researchers from the disease control center said genome sequencing showed the Hebei strains were different from that found in other parts of China and were unrelated to the strain in the U.K., but shared some similarities with versions found in Russia.Shijiazhuang is a city of about 11 million people and roughly 10 hours’ drive north from Wuhan in Hubei province, where Covid-19 first emerged in late 2019. The disease became a global pandemic within months, and has since infected more than 87 million people worldwide and killed more than 1.8 million.Hebei province’s health commission sent 1,000 medical personnel on Wednesday to Shijiazhuang to help the city with health-care needs and mass testing. There are plans to dispatch 2,000 more medical workers on Thursday.Chinese authorities are encouraging people to stay put in the cities where they work during the upcoming Lunar New Year vacation next month. Hundreds of millions of people traditionally return to their hometowns or travel during the extended holiday, which falls this year in mid-February.