China's travel agencies started to suspend planned trips to the Philippines amid concerns over the possible massive anti-China protests that may pose a threat to Chinese nationals.

Leading online travel agency Ctrip.com on Wednesday announced its decision to suspend its trips to the islands.

Under the current circumstances, "trips to the Philippines have potential safety risks", said the agency.

The Sunday flight from Beijing to Boracay, a tourism resort, has been canceled, China Youth Tourism Service(CYTS), one of China's leading travel agencies, said on its official micro blog.

CYTS said it will ensure customers are refunded and any losses will be recouped.

Some of the traveling industry's major businesses in China's major cities, including Shanghai and Guangzhou, have also suspended their services to the Philippines.

"Even if the agencies do not suspend their services there, I would not travel to the Philippines because of the current tension that is affecting bilateral ties," a female Guangzhou citizen surnamed Wu told reporters.

China's embassy in the Philippines has issued a safety alert for Chinese enterprises and nationals in the country ahead of massive protests against China.

The embassy's notice said that "massive" anti-China demonstrations are about to happen within days. Chinese nationals are advised to be on the alert and avoid going out, according to the notice issued by the embassy's economic and commercial section on Tuesday.

It also urges Chinese nationals to stay away from protesters, keep a low profile and abide by local laws.