More than 500 tourists from the Chinese mainland and Hong Kong have canceled their bookings with the Philippine Airlines (PAL), after the hostage incident took place on Monday, the airline said on Thursday.

"PAL is beginning to feel the initial impact of a Hong Kong government advisory warning, asking its residents to refrain from all travel to the Philippines. As of Wednesday, our Hong Kong station reported at least 558 Manila-bound bookings were canceled. The bookings consisted of tourists from Hong Kong, Beijing, Xiamen, and other points in China," PAL President Jaime J. Bautista said on Thursday.

Among those, at least 30 tourists from Hong Kong have canceled their trip to the southern city of Davao, scheduled for next month.

He added that two Hong Kong and Macao bound Filipino tourists also opted to change their destination in view of the current situation.

Bautista said that PAL has yet to determine the financial impact of the booking cancellations at this early stage.

About 6 percent of PAL's revenues comes from its operations to Hong Kong. PAL flies to Hong Kong five times a day. The airline also flies to Macao, Shanghai, Xiamen and Beijing.

"Hong Kong is a very important route for PAL," Bautista said. But he said so far, only flights from China have been affected by the cancellations.

Despite the negative travel advisory, PAL continues to mount five daily flights to and from Hong Kong.

"We're closely monitoring the situation and will decide soon whether we will maintain or reduce flights," Bautista said.

"We are optimistic that fears of traveling to the Philippines will be temporary," he added.

An ex-policeman turned gunman hijacked a tour bus carrying 21 Hong Kong tourists Monday morning in Manila. The incident ended with the deaths of eight tourists. The hostage taker was killed in police assault.