Heihe, a major port city in China's Heilongjiang province bordering Russia in the north, was urgently put under a lockdown on Thursday after one confirmed Covid-19 case was found, Global Times reported.

It is the third city that has imposed such rules in the latest resurgence of the virus, following the China-Mongolia border city of Ejin Banner and the transport hub Lanzhou.

Starting from Thursday, strict management measures will be imposed in all communities in Heihe, said a notice posted on the municipal government website.

It specified that all operating units in the city will suspend operation and production except for departments essential to residents' daily needs, and supermarkets and pharmacies can only operate within limited time and limited customer flow.

Residential communities and rural villages in Heihe will close off, leaving only one entry-exit that allows one person per household to pass once every two days, given that the neighbourhoods have not reported confirmed Covid-19 cases.

Gathering activities are also cancelled and banned across the city, the report said.

Traffic control will be in place, suspending all bus and taxi services, the notice said, adding that vehicles and personnel are not allowed to leave the city.

The lockdown comes after the city reported one confirmed case and three asymptomatic cases on Wednesday, which are the firsts to be found in Heilongjiang in the latest outbreak, not long after the province experienced a viral spike in late September.

The China-Mongolia border city of Ejin Banner in the Inner Mongolia Autonomous Region, one of the hard-hit areas that came under the spotlight for being the suspected source of the transmission chain in the latest Covid-19 flare-ups, tightened lockdown management for stranded tourists and local residents on Wednesday.

This comes after the city sacked the Party chief for dereliction of duty.

Lanzhou, capital of Gansu province which is considered as a transportation hub, closed off residential areas on Tuesday to prevent the further spread of the virus.