As President Ferdinand Marcos Jr. on Monday described as “concerning” the reported entry of a Russian submarine in the country’s exclusive economic zone (EEZ), the Philippine Navy (PN) clarified that the passage was not illegal.

“That’s very concerning. Any intrusion into the West Philippine Sea (WPS), of our EEZ, of our baselines, is very worrisome,” Marcos said in an interview in Marikina City on Monday.

“We will let the military discuss it with you,” he added.

Navy spokesperson for the WPS, Rear Admiral Roy Vincent Trinidad, confirmed the Russian submarine, identified as UFA 490, was sighted 80 nautical miles west of Cape Calavite, Occidental Mindoro on 28 November.

“The first time that we detected it, we were able to respond and track it,” he said. “Upon receiving the report, the Philippine Navy immediately deployed assets to monitor and address the situation, ensuring the security of Philippine waters.”

Trinidad noted there was “friendly” communication between the Philippine Navy and the crew of the Russian submarine when it happened to enter the country’s EEZ.

The Navy’s BRP Jose Rizal established radio communication with the submarine, followed by the confirmation of its identity, crew complement and navigational intent.

In responding to the radio challenge, the Russian vessel’s in command said they were awaiting improved weather conditions before proceeding to Vladivostok, Russia.

Trinidad said Philippine naval forces, including the Jose Rizal, escorted and monitored the submarine’s compliance with maritime regulations within the EEZ.

“We were surprised when we detected it, but then we responded immediately. We were able to establish communication and so far it was okay, we had a friendly exchange of information and they informed us where they were going,” he said.

Trinidad said the submarine’s passage through the Philippine EEZ was “not illegal.” Reports said the submarine actually surfaced.

Freedom of navigation

Citing the United Nations Convention on the Law of the Sea (UNCLOS), Trinidad explained that a foreign vessel may pass through the country’s EEZ under the “freedom of navigation.”

The Russian vessel was not conducting untoward maneuvers when it was spotted in the WPS, he added.

Trinidad said the UFA diesel-electric submarine was en route home to Russia when it was sighted.

He noted the Russian Pacific Fleet had just completed a passing exercise (Passex)-type joint naval exercise with the Malaysian Navy in the South China Sea a week ago.

In its report, the Russian Pacific Fleet’s press office said the submarine, escorted by the Pacific Fleet’s rescue tug Alatau, “had finished its official visit to the port of Kota Kinabalu in Malaysia and had conducted naval drills with ships of the Malaysian Navy.”

It added that the Russian and Malaysian vessels “practiced joint maneuvers, communication and other forms of cooperation.”

Trinidad said the Russian submarine was sailing in the northern part of the country, leaving the Philippine EEZ as of 1 December.

Asked if the submarine needed permission to pass through Philippine waters, he replied: “No need because under the freedom of navigation, if you are surfaced or submerged, it is granted under UNCLOS.”

Some senators, including Jinggoy Estrada and Joel Villanueva, had expressed alarm over the sighting.

“This situation is concerning, raising significant questions about the stability and security of our already volatile maritime domain, which is a flashpoint for geopolitical tensions,” Estrada said in a statement.

He urged the Department of National Defense and the Department of Foreign Affairs to immediately take action and clarify the intention behind what he described as an “incursion.”

“We thank our Philippine Coast Guard and the Philippine Navy for their unwavering commitment as the guardians of our seas, ensuring the safety and security of our maritime territory,” Villanueva said.