China will further enforce strict control over international passenger flights that possess a high risk of imported COVID-19 cases, the country's civil aviation regulator said Tuesday.

The passenger load factor of inbound flights that are of relatively high risks should not exceed 75 percent, the Civil Aviation Administration of China (CAAC) said in a statement, citing the grim situation of pandemic control overseas.

The rule applies to international flights deemed high-risk in China's latest edition of the pandemic-control guide for airlines as well as to flights that have resumed operations after previous suspensions due to imported cases.

Flights operated by the same airline on the same route with over five passengers testing positive for COVID-19 for three weeks in a row must also adhere to the 75-percent cap in passenger load.

The CAAC will continue its reward and suspension policy, putting on hold high-risk flights and allowing airline operators to increase flights if all inbound passengers on an airline test negative for COVID-19 for a certain period, it said.

So far, the CAAC has enforced 31 flight suspensions and canceled 52 inbound flights.