Medical staff members inquire about a patient at a quarantine and isolation center in Johannesburg, South Africa, July 3, 2020.Photo:Xinhua

One passenger on Air China flight CA868 from Johannesburg, South Africa, to Shenzhen, South China's Guangdong Province, tested positive for COVID-19 on September 2, marking the first imported case from South Africa to China, which may trigger a temporary suspension of the airline to China, also known as a "circuit breaker", the Embassy of China in South Africa announced.

More than 60 passengers on the same flight have since been put under medical observation. If additional cases of COVID-19 from the flight will be reported, a "circuit breaker" may be carried out, the embassy wrote in a notice posted on its official website on Monday.

The patient followed the embassy's requirements to take a COVID-19 test in the designated institutions before boarding and submitted the test results to receive the "green" health code. However, the person didn't obey the rules in quarantining at home after getting tested and instead went outside with family members who lived together. The patient's family members have since been confirmed with the virus, according to the notice.

"A lack of strict home quarantine after testing" is the most likely cause of the patient's infection, the embassy said.

The embassy called on all Chinese citizens living in South Africa to ensure they subject themselves to home quarantine after testing for COVID-19 (which includes separating themselves from family members that may be not in quarantine), in order to reduce the risk of infection.

The Civil Aviation Administration of China previously triggered several "circuit breakers" as passengers returned positive test results for COVID-19, including flights from Etihad Airways, China Eastern and SriLankan Airlines. Most of the airlines have been suspended for only one week.