BEIJING (Reuters) - Hong Kong flag carrier Cathay Pacific Airways Ltd 0293.HK said on Saturday it had suspended a pilot arrested during anti-government protests in Hong Kong and that "overly radical" staff would be barred from crewing flights to the mainland.

FILE PHOTO: A Cathay Pacific Airways Airbus A350-900 airplane approaches to land at Changi International Airport in Singapore June 10, 2018. REUTERS/Tim Chong

The move followed China’s aviation regulator demanding the airline prevent staff involved in some of the protests in Hong Kong from operating flights to China, describing it as a safety issue.

The broadside poses a major commercial challenge to Cathay, which already reported tumbling bookings last week as a result of the anti-government protests gripping Hong Kong.

The airline said on Saturday in response to customer queries that the pilot had been removed from duties on July 30 “in line with our standard process” and had not flown since July 15.

“We express no view whatsoever on the subject matter of any proceedings to which he may be subject,” the company added in a statement.

For the past two months Hong Kong has been embroiled in increasingly violent anti-government street protests, which a Chinese official described last week as the greatest crisis since its return from British to Chinese rule in 1997.

The Cathay pilot, whom the company did not name, was among over 40 people charged with rioting, during clashes with police near Beijing’s main representative office in the city.

In a separate memo on Saturday, Cathay Pacific CEO Rupert Hogg told staff that in order to comply with the new regulatory demands it would not allow any crew supporting protests in Hong Kong to staff flights to the mainland from midnight on Aug. 10.

“Cathay Pacific Group employees who support or take part in illegal protests, violent actions, or overly radical behaviour shall be immediately suspended from any activity involving flights to the mainland,” he said.

The memo added that the airline would submit identification details of all crews flying to or over mainland China to authorities there for approval.

“Cathay Pacific Group’s operations in mainland China are key to our business,” he said.