President Duterte had raised the issue of Chinese warships’ unauthorized passage in Philippine waters during his meeting with Chinese President Xi Jinping, but the Philippine leader was told that China does not need to seek permission whenever it sails into international waters, Defense Secretary Delfin N. Lorenzana said on Wednesday.

President Duterte’s official visit to Beijing where he met with his Chinese counterpart was made ahead of the first Asean-US Maritime Exercise (AUMX), which began this week in Thailand, and was being participated by Filipino sailors and the BRP Ramon Alcaraz, one of the frigates of the Philippine Navy.

“Yes, it was raised by the President. The reply of President Xi is that international law does not require ships passing through territorial waters of another country. He reassured President Rodrigo Roa Duterte that their naval ships are not coercing, or targeting, the Philippines,” said Lorenzana.

Xi maintained that the Chinese Navy vessels were allowed to transit through the country’s waters, after apparently invoking the United Nations Convention on the Law of the Sea wherein innocent passage is allowed, although Philippine military officials said that in some cases, the voyage that were taken were not in any way in the direction of innocent passage.

Since February this year, Chinese warships have passed through the Sibutu and Balabac Straits in Tawi-Tawi and Palawan, respectively, for 14 times, but the vessels have kept their identities by turning off their automatic identification system and refused to answer challenges made by Philippine Navy vessels.

While the Chinese military vessels were supposed to sail in straight course while transiting in the country’s maritime waters, supposedly in exercise of their innocent passage, officials however said that the ships had sometimes deviated from their course, actions that Lorenzana called as “irritants” along with the unauthorized voyages.

President Duterte’s raising of the thorny security issue with China took place as the Asean member- states launched their first-ever maritime exercise with the United States, which assembled ships, aircraft and more than a thousand American and regional troops.

The AUMX was the first direct military engagement by the US with the whole region as it increases, both its presence and activities in Southeast Asia amid the tension with China over the South China Sea where Beijing has reclaimed islands and turned them into military fortresses.

Ahead of the maritime exercise, which took off at the Sattahip Naval Base in Thailand, the BRP Ramon Alcaraz carried out a trilateral sail with Brunei Darussalam’s offshore patrol vessel KDB Darussalam and Vietnam’s Pohang-Class HQ-18 vessel while on their way to participate in the war games.

The frigate met with KDB Darussalam at the Kingston Shoal in Brunei before they sailed together to meet HQ-18. The three vessels carried out a series of drills while they were steaming to Thailand, according to Lt. Ryan Luna, public affairs officer of the Philippine Navy’s Naval Task Group 80.5

The Alcaraz and the two vessels from Brunei and Vietnam combined into a naval task group wherein the Philippine Navy was designated as the task group commander. Capt. Hilarion Cesista headed the Philippine contingent to the AUMX.

Rear Adm. Murray Joe Tynch III, commander of the Logistics Group of the US Navy in Western Pacific said the ongoing Asean-US maritime exercise was a significant event and a positive step toward building a more interconnected region, which is a “key” in maintaining stability and security in the Asean.

“One of the unique characteristics of AUMX is that we’re exercising a combined task force structure, and this is exactly how navies structure themselves in real world scenarios to work together and best leverage their forces. We really value each other’s perspective and information capabilities,” he said.

“The challenges we face in the maritime domain extend beyond what any single nation can handle, and that’s where partners and allies are force multipliers for peace and interoperability. That’s an unparalleled advantage that no competitor or rival can match. I fully believe we are stronger when we sail together,” Tynch added.

When asked how the exercise would relate to the current problem in the South China Sea, Tynch said it should build the skills and capabilities of the participating navies in dealing with it, although he clarified that the AUMX was not poised against “anyone,” including China.

“What I’d like to make clear about AUMX is the focus of it, really, which is to enhance skills that are applicable to maritime security throughout international waters. So, the concept of AUMX this year is to enhance situational awareness and interoperability for all of Asean and for the US as well. So, that’s the focus of this, really, on skills that are applicable throughout the world for maritime security,” he said.