Following 57 days without reporting any new cases, at least 137 people have been tested positive for the deadly virus. The Xinfandi food market in Beijing is thought to be the source of the outbreak.
The food market, which has been closed, reportedly supplies up to 80 percent of meat and vegetables in the city.
According to the BBC, at least 27 neighbourhoods have been placed at medium risk while another close to the market is thought to be at high risk.
People in neighbourhoods in either category are not allowed to leave.
The Beijing government said “relevant people” from the market will not be allowed to leave regardless of the neighbourhood they live in.
Although images show people are being tested in the area, local reports claim as tests are in demand, three centres will not be able to provide any until July.
Railway services will not resume until at least July 7 with schools, sports centres, swimming pools and gyms all suspended.
Chen Bei, deputy secretary general of the Beijing Municipal People’s Government, said: “Beijing faces serious danger of imported cases and spread in the city and the country.”
Despite the new outbreak, government officials called on employers to continue regular operations but encouraged more remote working.
READ MORE: China second wave: 28 neighbourhoods in Beijing under lockdown
The country has ceased imports from European salmon suppliers over fears of a link to Xinfadi market.
Chinese state newspapers have reported that the virus has been identified on surfaces preparing salmon.
This is despite experts saying that the fish itself is unlikely to carry Covid-19.
The reports have led to major Beijing supermarkets to remove salmon from their shelves.
Genetic traces of the virus from Xinfadi market have suggested that the resurgent outbreak may have come from Europe.
Wu Zunyou, chief epidemiologist at the Chinese Centre for Disease Control and Prevention told CGTN: “It clearly indicates the virus strain is different from what it was two months ago.
“The virus strain is the major epidemic strain in European countries.
“So it is from outside China brought to Beijing.”
Keith Neal said any link to salmon was probably the result of cross-contamination.
The emeritus professor of the epidemiology of infectious diseases at Britain’s University of Nottingham said: “Markets can be crowded places, so, like in Wuhan, [they] help fuel the spread.”
It was previously reported in May that the strain of coronavirus seen in Europe was a mutated version from the original strain in China.
Though the coronavirus outbreak was first spotted in Wuhan, the curve appeared to have been flattened before the cases in Beijing emerged.