"We have to be careful as we're near Guan, where COVID cases were reported today", said a volunteer security officer surnamed Wang.
People line up to get their nucleic acid test in the courtyard of a hospital following the outbreak of the coronavirus disease in Beijing. Of the 85 locally transmitted confirmed cases, 82 were reported in north China's Hebei Province, two in Liaoning Province, and one in Beijing.
Suihua city in Heilongjiang - home to more than 5.2 million - was sealed off on Monday after reporting one confirmed case and 45 asymptomatic cases.
The Chinese mainland on Tuesday reported 115 newly confirmed COVID-19 cases, of which 107 were locally transmitted and the rest arrived from outside the mainland, the National Health Commission said Wednesday.
Over 70 percent of confirmed cases distributed are in rural areas, which have the tradition of holding weddings ahead of the Lunar New Year.
Much remains unknown about the origins of the coronavirus and China has been sensitive about accusations of a cover-up that delayed its initial response and allowed the virus to spread. A health expert affiliated with the WHO said previously that expectations should be "very low" that the team would reach a conclusion from its trip to China.
"More than 20k people in 12 villages in Zengcun county of Gaocheng district in N China's Shijiazhuang have been transferred to designated quarantine areas for medical observation since Monday". The secretary of the Heilongjiang Provincial Party Committee, who was in Beijing for a seminar returned to Heilongjiang overnight and declared the state of emergency.
Shanxi province has also limited internal travel and rolled out mass testing, after a patient from neighbouring Hebei province was reported to have travelled there.
The Chinese government sealed off a city of 4.9 million people and imposed strict travel restrictions on several other parts of the country after a sudden surge was witnessed in the number of COVID-19 positive patients.
Hebei province has put three cities - Shijiazhuang, Xingtai and Langfang - into lockdown, while Beijing city authorities have stepped up screening and prevention measures.
Across China, the number of new asymptomatic cases rose to 81 from 76 a day earlier. Far fewer are expected to hit the road this year, and many provinces have asked migrant workers to stay put during the break.
Underscoring the risk of the spread, the city of Changchun - the capital of northeastern Jilin province - reported seven new asymptomatic patients on January 11, four of whom had travelled from Wangkui recently.
The total number of confirmed COVID-19 cases reported in mainland China now stands at 87,591, while the death toll remained unchanged at 4,634.