Staff members disinfect the cabin of an airplane after its arrival at the Haikou Meilan International Airport in Haikou, south China's Hainan Province, Jan. 31, 2020. (Photo by Pu Xiaoxu/Xinhua)

Beijing city will gradually resume direct international flights starting Thursday as the COVID-19 outbreak has been contained, the Chinese civil aviation regulator announced on Wednesday.

Starting from Thursday, nine flights will operate from eight countries that have reported fewer infections, including Thailand, Cambodia, Pakistan and Canada. The first direct international flight will be operated by Air China from Phnom Penh, capital of Cambodia, according to a statement on the website of the Civil Aviation Administration of China (CAAC).

In order to control the cross-border spread of the global pandemic, the CAAC ruled that it would impose stricter anti-COVID-19 prevention measures based on an existing "circuit breaker" mechanism.

The regulator stressed that if three or more confirmed cases are found on an international flight into Beijing, the flight will be re-directed to other Chinese cities, while the number of overseas passengers arriving at Beijing Capital International Airport will be limited.

During trial operations, direct international flights to Beijing will have a passenger cap of around 500 each day, and they will be tested for COVID-19 twice and sent into collective quarantine for 14 days, according to the authorities.

In March, China started to redirect all international flights scheduled to arrive in Beijing to airports in 12 other Chinese cities, where passengers must go through customs clearance and quarantine, with those passing quarantine inspection being permitted to fly to Beijing on their original flights.

As of Tuesday, a total of 511 international passenger flights had been scheduled to use the first entry points.