China has recorded 108 new coronavirus cases, marking the highest daily tally for more than five weeks and fanning fears of a second wave.
More than 90 per cent of these infected people have entered the country from abroad following the lift of travel restrictions.
Having largely stamped out domestic transmission of the disease, China has been slowly easing curbs on movement as it tries to get its economy back on track.
But there are fears that a rise in imported cases could spark a second wave of COVID-19.
The northeastern border with Russia has quickly become a frontline in the fight against a resurgence of the coronavirus epidemic.
The 108 new cases reported on Sunday are up from 99 a day earlier, marking the highest daily tally since March 5.
The total number of confirmed cases in mainland China now stands at 82,160 as of Sunday, and 3,341 people have died.
On the worst day of China's outbreak, on February 12, there were over 15,000 new cases recorded.
Though the number of daily infections across China has dropped sharply from that peak, China has seen the daily toll creep higher after hitting a trough on March 12.
It's largely been blamed on international travel. Imported cases accounted for a record 98 of the 108 reported on Sunday.
Half involved Chinese nationals returning from Russia's Far Eastern Federal District, home to the city of Vladivostok.
The border to Russia is closed, except to Chinese nationals who are crossing into the Heilongjiang province.
The route has become one of few options available for people trying to return home after Russia stopped flights to China except for those evacuating people.
Chinese cities near the Russian frontier are tightening border controls and imposing stricter quarantines in response, as cases in Russia creep up to 18,400.
Suifenhe and Harbin, the capital of Heilongjiang, are now mandating 28 days of quarantine as well as nucleic acid and antibody tests for all arrivals from abroad.
'Our little town here, we thought it was the safest place,' said a resident of the border city of Suifenhe, who only gave his surname as Zhu.
'Some Chinese citizens - they want to come back, but it's not very sensible, what are you doing coming here for?'
Streets in Suifenhe were virtually empty on Sunday evening due to restrictions of movement and gatherings announced last week.
Authorities took preventative measures similar to those imposed in Wuhan, the central Chinese city where the pandemic ripping round the world first emerged late last year.
In Shanghai, authorities found that 60 people who arrived on Aeroflot flight SU208 from Moscow on April 10 have the coronavirus, Zheng Jin, a spokeswoman for the Shanghai Municipal Health Commission, told a press conference on Monday.
Residents in Suifenhe said a lot of people had left the city fearing contagion, but others put their trust in authorities' containment measures.
'I don't need to worry,' Zhao Wei, another Suifenhe resident, told Reuters.
'If there's a local transmission, I would, but there's not a single one. They're all from the border, but they've all been sent to quarantine.'
Transmission of the coronavirus between people in China has reduced massively since Wuhan and 16 of its neighbouring cities in the Hubei province went into lockdown on January 23.
Daily new cases dropped to zero, and the indication that the virus had been contained allowed for the relaxation of lockdowns.
Researchers in Hong Kong have warned that premature easing of restrictions could leave to a second wave of cases because there are still people who have no immunity against the disease.
Kathy Leung of The University of Hong Kong estimated that relaxing draconian measures 'would increase the cumulative case count exponentially'.
They wrote in The Lancet: 'Although the aggressive countermeasures appear to have reduced the number of reported cases, the absence of herd immunity against COVID-19 suggests that case counts could easily resurge when these interventions are relaxed... particularly from overseas importation.'
As countries across the world battle their 'first wave' of the pandemic, there are concerns China is now approaching its second.
This article has been adapted from its original source.
