MANILA — The Philippines stressed Tuesday that the country was not drifting into the military orbit of China, despite President Rodrigo Duterte’s perceived warming ties with Beijing and fresh concerns about Beijing’s aggressiveness in the South China Sea.

The assurances were made as top American diplomats and defense officials met with their Philippine counterparts in Manila for annual strategic talks aimed at strengthening relations between their two militaries. The Philippines has been America’s closest Southeast Asian strategic ally for the last seven decades, with Washington a consistent source of military aid and arms sales to Manila.

Manila’s envoy to Washington, Jose Manuel Romualdez, said that the two sides discussed “shared concerns,” particularly violent extremism and the continued presence of Islamic State militants in the country. Two years ago, American intelligence helped the local army beat back militants seeking to take over the city of Marawi on the southern island of Mindanao.

“The relationship is very strong,” Mr. Romualdez told reporters, adding that the United States had said it would continue its freedom of navigation patrols to prevent Chinese aggression in the South China Sea. The maritime region has recently seen a spike in aggressive Chinese moves against smaller countries like the Philippines and Vietnam.