The Philippine Navy said a Chinese aircraft carrier battle group had passed near its northern maritime boundaries in the run-up to a six-day maritime exercise with the US that began as part of their annual Balikatan military drills.
The coordinated naval drills, focused on enhancing interoperability, maritime domain awareness, and regional security, would be carried out within Philippine waters, spanning from the vicinity of Subic Bay up to Northern Luzon, the Philippine military said.
Japan and other regional partners are increasingly taking part in Balikatan, which means "shoulder-to-shoulder," amid tensions with China over its activities in the South China Sea and around Taiwan.
A Japanese navy ship is joining the exercises.
The drills are concentrated in the northern and western parts of the archipelago nation, near the potential flashpoints of the South China Sea and Taiwan.
'Full battle test'
Rear Admiral Roy Vincent Trinidad, Philippine Navy spokesperson for the South China Sea, on Thursday confirmed the sighting of the Chinese naval formation early on Tuesday, about 100 nautical miles off Burgos, Ilocos Norte.
Led by the aircraft carrier Shandong (CV-17), the battle group consisted of six warships, including frigates and destroyers, and two support vessels, Trinidad said.
The flotilla reportedly came within three nautical miles of the Philippines' northern islands.
"This is quite close, but these are allowed under UNCLOS, under the right of innocent passage provided that it is continuous and expeditious," said Trinidad, adding that the vessels were nearly outside the country's exclusive economic zone by Wednesday night.
The Philippine Navy said the sighting, while closely monitored, is not considered alarming. Still, the timing of the Chinese passage underscores the strategic weight of the ongoing Balikatan drills, which have grown in scale and complexity in recent years.
"We do not speculate on the intention of their warships in our waters," Trinidad said. "What we do is we challenge them, we monitor them, to ensure that they traverse continuously and expeditiously."
More than 14,000 Filipino and American soldiers are participating in this year's Balikatan exercises, which run from April 21-May 9, for a "full battle test" between the two defence treaty allies in the face of shared regional security concerns. China has said the drills are provocative.
