Hong Kong, Jul 9 (IANS): Foreign pilots and cabin crew are refusing to fly to Hong Kong over the potential consequences of testing positive for COVID-19, sources said on Thursday.

On Thursday, United Airlines and American Airlines (AA) became the first carriers to suspend flights to the city over new mandatory testing rules for aircrew.

A coalition of European and North American carriers has also proposed testing aircrew before they depart for Hong Kong, the sources told the South China Morning Post (SCMP) newspaper.

Airlines were concerned all crews could be quarantined for 14 days if one positive test was returned, something flight staff find unacceptable.

Companies fear subsequent quarantining would throw flight operations into chaos and are willing to cancel flights and give up precious revenue to resolve the issue, the sources added.

The sudden cancellation of the relaunched United and AA services stem from concerns raised by both companies' pilots unions over the testing.

American, which was expected to resume passenger flights to Hong Kong this week, has suspended services until August 5.

According to the sources, a counter-proposal from airlines is seen as a workaround, and involves testing aircrew on departure to weed out positive cases before they arrive in Hong Kong.

"COVID-19 testing before departure can be carried out at short notice if required," a source told the SCMP newspaper, stressing the need to take precautions.

The development comes after Hong Kong's Centre for Health Protection announced on Tuesday that all air and shipping crew members arriving in the city must give deep-throat saliva samples for coronavirus testing.

The stricter measures for people exempted from quarantine were imposed after some pilots were among those found to be infected with COVID-19.