The passage of a Chinese aircraft carrier group within the Philippine waters is ''no cause for alarm'', the Armed Forces of the Philippines (AFP) spokesperson for the West Philippine Sea said Tuesday.

Roy Vincent Trinidad, a retired rear admiral, said the aircraft carrier strike group of China transits within the Philippine waters every May to June and October to November.

"It is no cause for alarm. It is not the first time that a carrier battle group of the (People Liberation Army) PLA Navy has transited international and Philippine waters. What happened recently is part of an annual twice a year, periodic aircraft carrier operation exercise, training exercise, conducted by the PLA (People's Liberation Army) Navy," he said.

Trinidad said the usual route of the Chinese aircraft carrier "is coming from the northern part of the country passing through Bashi or Balintang Channel going down south to our eastern seaboard down south, all the way as far as Australia coming back up to Sibuto passage then to the West Philippine Sea."

However, Trinidad said based on the monitoring of the AFP, the Chinese Navy's Liaoning Carrier Strike Group "passed to the western seaboard" and came close within 15 miles to the Philippine landmass.

"(There) is no possible alarm. It is a periodic activity. Our maritime domain awareness is constant, active, and monitoring them," he said.

"There was no response whatsoever to the challenges that we gave them. But our monitoring was constant the moment we first noticed them entering our maritime domain, monitored by the coast guard by the AFP, Philippine Air Force. This was a very good opportunity for us to be able to test our systems and procedures on how to track a high value asset navigating through our maritime domain," he added.

Trinidad said "a carrier strike troop usually has a package composed of destroyers, air-defense destroyers, surface assets, replenishment ships, and is always expected to have a submarine."

"The route of the Liaoning was to the western seaboard, and it exited on the southern border of the country," he added. Robina Asido/PHS