Cathay Pacific has warned its employees that those who "support or participate in illegal protests" in Hong Kong could be fired.

Hong Kong’s largest airline outlined its zero tolerance approach in a memo sent days after Chinese authorities took steps to prevent Cathay workers who participate in protests from flying to mainland China or passing through the country's airspace. Cathay said that it would comply with that rule.

Chief executive Rupert Hogg reiterated that Cathay Pacific employees would also face “disciplinary consequences” if they get involved in the pro-democracy protests. He further mentioned that “These consequences could be serious and may include termination of employment.”

In fact, China's Civil Aviation Administration said Friday that it would ban Cathay employees who support or take part in "illegal demonstrations, protests and violent attacks, as well as those who have had radical behaviors" from working on flights in China's airspace. The agency also said it will require Cathay to submit identification details about all relevant crews for approval prior to takeoff.

The protests in Hong Kong have infuriated Beijing and left Cathay Pacific in a difficult position.  It has already suspended a pilot who has been accused of rioting after allegedly participating in the Hong Kong protests.