Blinken was in Manila with US Defense Secretary Lloyd Austin as part of an Asia-Pacific tour to strengthen Washington's latticework of alliances aimed at countering Beijing.

Blinken also said Tuesday that the United States shares the Philippines' concerns about escalatory actions China has taken in the South China Sea.

Blinken's remarks followed security talks in Manila between him, Secretary of Defense Lloyd Austin and their respective Philippine counterparts, Enrique Manalo and Gilberto Teodoro.

Later on Tuesday, the European Union's foreign policy chief Josep Borrell said the EU wanted to guarantee peace in the South China Sea and told Vietnam the bloc could help boost its maritime security and cybersecurity capabilities. 

The Southeast Asian country is at odds with China over its boundaries in the South China Sea, a crucial shipping waterway which Beijing claims almost in its entirety - a stance that has caused tensions with other countries in the region as well.

In a meeting with Vietnam's Foreign Minister Bui Thanh Son in Hanoi, Borrell, who is approaching the end of his five-year term as High Representative for EU Foreign Affairs, said the 27-country bloc had a "direct interest in maintaining peace and stability" in the South China Sea, where over a third of EU imports and more than 20 percent of its exports transit.

"The EU can be a smart enabler for peace and security," he told reporters during a joint press conference with Son, noting the EU could "enhance Vietnam's capabilities in cybersecurity, maritime security and crisis management".

Vietnam has relied for decades on military gear from Russia, but since 2022 has been publicly saying it wants to diversify its security equipment, and is in talks with multiple countries, including in Europe, over possible defence supplies.

Borrell stressed that the fulfilment of international law, which Vietnam invokes in the South China Sea, should be applied everywhere, including in Ukraine.