The United States and the Philippines reaffirmed their “ironclad” alliance on Monday as they opened the 41st iteration of the Balikatan, marking the 75th anniversary of the Mutual Defense Treaty.

Speaking at the opening ceremony, U.S. Chargé d’Affaires Y. Robert Ewing said the long-standing defense pact remains a cornerstone of peace and stability in the Indo-Pacific.

“For three-quarters of a century, this treaty has stood as a living testament to the enduring strength of the U.S.-Philippines relationship, adapting to meet new challenges while remaining firmly grounded in our shared values, democratic principles, and common purpose,” Ewing said.

The annual Balikatan exercises — derived from the Filipino term meaning “shoulder to shoulder” — highlight the close military cooperation between the two allies. Ewing said the exercise reflects a partnership that goes beyond security, emphasizing shared responsibilities in addressing humanitarian crises, natural disasters and regional threats.

This year’s drills are set to be the largest in Balikatan history, involving combined and joint operations across land, sea, air, cyber and space domains.

Alongside U.S. and Philippine forces, troops from partner nations including the United Kingdom, Australia, Canada, France, Japan and New Zealand are participating, underscoring a broader network of security cooperation in the region.

“These activities reflect not only the complexity of today’s security environment but also our shared commitment to readiness, interoperability and collective defense,” Ewing said.

Philippine military chief Romeo Brawner Jr. and other defense officials led the ceremony, which formally launched weeks of joint exercises aimed at strengthening operational coordination and response capabilities.

Beyond military drills, officials highlighted the role of humanitarian and civic programs under Balikatan, including the construction of classrooms, health facilities and multipurpose buildings, as well as medical missions focused on trauma care, preventive medicine and public health.

Ewing said these initiatives demonstrate a “whole-of-society approach,” extending the alliance’s impact to local communities and improving lives on the ground.

“Balikatan is more than a military exercise, just as our alliance is more than a security partnership,” he said. “This is our alliance in action, delivering meaningful impact where it matters most.”

The exercises come amid evolving regional security challenges, with both countries emphasizing the need for continued cooperation to maintain a free and open Indo-Pacific.

Over the coming weeks, forces from participating nations are expected to conduct coordinated operations and engagements designed to enhance interoperability and strengthen long-term defense ties.

Ewing said the relationships built during the exercises — from senior officials to individual service members — are expected to endure beyond the drills and contribute to a more resilient partnership between the United States and the Philippines.