China's growing "coercive actions" against Philippine vessels in the West Philippine Sea may be considered as being "short of an armed attack," a ranking military official said.

Armed Forces of the Philippines-Western Command chief, Vice Admiral Alberto Carlos, said in a television interview that China's actions are becoming increasingly dangerous.

"Well, it's already escalating. As I've said, they started using lasers, and now this, water cannons. So expect more coercive actions from China, short of an armed attack," Carlos said.

"Next is probably the ramming, and they may also attempt to board our vessels, which is something that we will not allow them to do," he said. "All this is short of an armed attack because they know that it will trigger our mutual defense treaty with the United States."

Carlos said they are assessing the escalation of China's actions against the Philippines "legitimately operating" in its exclusive economic zone.

He said that as of yesterday, there were still nine Chinese vessels roaming around Ayungin or Second Thomas Shoal, where Philippine vessels trying to resupply troops aboard the BRP Sierra Madre were blasted with water cannons, and one vessel, with Armed Forces Chief of Staff Romeo Brawner Jr. on board, was rammed.

He said the Chinese vessels had been entering the Philippines' exclusive economic zone, prompting the Philippines to send out rubber boats to try to get them to leave the EEZ.

National Security Council spokesperson Jonathan Malaya said that the Philippines, United States and Japan are burning the lines on how to sustain their maritime security operations in the WPS.

Malaya said National Security Adviser Eduardo Año spoke with his counterparts, Takeo Akiba of Japan and Jake Sullivan of the US on Wednesday.

"NSA Año thanked his counterparts for their unwavering support for the Philippines' lawful exercise of its maritime rights within its EEZ, in accordance with international law, particularly the July 2016 arbitral award," he said.

Año told Akiba and Sullivan of President Ferdinand Marcos Jr.'s statement that the Philippine government remains undeterred in defending the nation's sovereignty, sovereign rights, and jurisdiction in the WPS.

On the other hand, the Japanese Ministry of Foreign Affairs lauded the Philippines for showing restraint over the Chinese Coast Guard's harassment in the WPS.

"Japan highly appreciates the Government of the Philippines for having consistently complied with the Arbitral Tribunal's award as to the disputes between the Republic of the Philippines and the People's Republic of China regarding the South China Sea and shown its commitment to the peaceful settlement of disputes in the South China Sea," it said in a statement issued on Wednesday night.

Reiterating "serious concerns" on the increasing tensions in the area, the Japanese government said it will continue to support Manila's longstanding objections to "unlawful maritime claims, militarization, coercive activities and threat or use of force in the South China Sea."