The Philippine, US and Japanese militaries conducted joint exercises this week over the Bashi Channel that separates the Philippines from Taiwan, officials said Friday.
Aircraft from the three nations patrolled over the Philippines' northernmost Batanes islands in drills aimed at showcasing their "ability to operate seamlessly together in complex maritime environments", the Philippine military said in a statement.
It marks the first time that so-called Multilateral Maritime Cooperative Activities (MMCAs) involving the countries have expanded beyond the South China Sea, where the Philippines and China have engaged in repeated clashes over disputed territory.
Little more than 100 kilometers (60 miles) separates the Philippines and self-ruled Taiwan, which China views as its territory and has not ruled out taking by force.
"Air operations were conducted within airspace over Philippine territory and its territorial sea, north of Luzon," the Philippine military said in a statement, adding naval vessels had stayed west of the Batanes island chain.
Armed forces public affairs chief Colonel Xerxes Trinidad told AFP it was the "first time" MMCA operations had been conducted in the "said operational box".
The military's statement said that box extended "up to the northern tip of Luzon, particularly Mavulis Island", which hosts small Philippine navy and marine detachments.
China's military reacted angrily to the drills on Friday.
"The Philippines co-opted countries outside the region to organize the so-called joint patrols, disrupting peace and stability in the region," said Zhai Shichen, spokesperson for the PLA's Southern Theater Command.
He added that China had conducted a "routine patrol" of the South China Sea from February 23 to 26.
In November, Japanese Prime Minister Sanae Takaichi sent relations with Beijing into a tailspin by suggesting that Tokyo could intervene militarily in any attack on Taiwan.
Beijing imposed export restrictions and warned its citizens against visiting Japan, while accusing Tokyo of attempting to "revive militarism".
Japan's defense minister upped the ante by saying on Tuesday that Tokyo planned to deploy surface-to-air missiles on one of its remote western islands located near Taiwan by early 2031.
In August, Philippine President Ferdinand Marcos warned that the Philippines would be dragged "kicking and screaming" into any war over Taiwan.
"I hope it doesn't happen... But if it does, we have to plan for it already," he said, citing the large numbers of Filipinos working in Taiwan.
The Philippine-US-Japanese exercise took place over six days and concluded on Thursday. It included a live-fire gunnery exercise conducted by the guided missile frigate BRP Antonio Luna.
