MANILA — The Philippine Navy on Friday condemned the reported use of flares by Chinese forces against a Philippine aircraft during a patrol over the West Philippine Sea (WPS), calling the action “illegal, unprofessional, and unsafe.”

“Number one, the activity of the Philippine Coast Guard was legal. It was within the bounds of domestic law and international law,” Philippine Navy spokesperson for WPS Rear Admiral Roy Vincent Trinidad told reporters.

“Secondly, the firing of flares by the Chinese Communist Party is illegal, unprofessional and unsafe. These actions are designed to regularize or normalize their illegal presence in our maritime domain,” he added.

The Philippine Coast Guard (PCG) said Chinese forces fired flares at a PCG aircraft conducting a routine maritime patrol over the WPS.

PCG spokesperson for WPS Rear Admiral Jay Tarriela said the incident took place during a maritime domain awareness (MDA) flight over the Kalayaan Island Group.

He also said the flares were directed at a PCG Caravan aircraft operating near Panganiban Reef and Zamora Reef.

Trinidad said Philippine forces will continue their operations despite such incidents.

“We will not be deterred from performing our functions, our mandate of patrolling the seas and the skies in spite of all of these illegal, coercive and aggressive actions being done against us.”

“We will be there to protect and to show the Philippine flag.”

Tensions in the area persist as Beijing claims almost the entire South China Sea, a major global trade route carrying more than $3 trillion worth of annual shipborne commerce, including areas also claimed by the Philippines and other neighboring countries.

The Philippine government refers to portions of the South China Sea within its exclusive economic zone as the West Philippine Sea to assert its maritime claim.

The West Philippine Sea covers maritime areas on the western side of the Philippine archipelago, including the Luzon Sea and waters surrounding the Kalayaan Island Group and Bajo de Masinloc.

In 2016, the Permanent Court of Arbitration in The Hague ruled in favor of the Philippines, saying China’s claims in the South China Sea had “no legal basis.”

China has since refused to recognize the ruling.