Flocks of Myanmar inhabitants flee to Ruili, SW China's Yunnan Province on November 22. Photo: Cui Meng/GT

A newly reported COVID-19 infection has triggered the lockdown of a residential complex in a Chinese city bordering Myanmar in Southwest China's Yunnan Province on Saturday afternoon, and the unknown source of the possible infection sparked concerns over illegal crossings. 

The infected, diagnosed as asymptomatic patient, is a 32-year-old Burmese and tested positive on Saturday, authorities said on Sunday.

After the suspected patient was detected, the neighborhood — Aoxing Shiji in Ruili — was put under lockdown to prevent a possible spread of the disease, the Ruili anti-epidemic authority announced on Saturday. 

Residents are required to stay in their homes during the lockdown period. The anti-epidemic group will provide residents with support. 

A source told the Global Times that the suspected patient surnamed Chen went to the Jingcheng Hospital in Ruili on Thursday and was diagnosed as a suspected case on Saturday. Whether Chen is actually infected will require further examination.

It is not known when, where or how Chen may have been infected, unnerving residents in the city, which has not seen domestic cases for months. But there was speculation that illegal border crossings may be the reason, as Ruili borders the Myanmar city of Muse.

The Global Times learned that land ports linking Myanmar and China have been closed to passengers since the early days of the epidemic and freight truck drivers are under epidemic-control measures.  

With a population of more than 200,000, Ruili has lots of interchanges with Myanmar, including jade trade. 

Border control authorities in Yunnan, which shares 1,941 kilometers of borderline with Myanmar, Laos and Vietnam, have been on high alert, implementing strict measures during the epidemic.

Myanmar reported 201 new COVID-19 cases on Sunday morning, bringing the total number of infections to 2,796, according to a release from its Ministry of Health and Sports.