"Well, this is essentially an agreement between the United States, Japan, and the Philippines. Our cooperation in terms of maintaining security and freedom of navigation in the South China Sea. That is the essence of it. And, of course, it will contain more details in the sense of how, in terms of cooperation, it will be implemented," Marcos said ahead of his departure to the US capital, as quoted by Philippine news agency GMA.

In late March, Politico reported that the three countries would announce plans to launch joint maritime patrols in the South China Sea following a series of incidents involving Chinese and Philippine ships around disputable parts of the sea.

Also in March, the Philippine armed forces said the China Coast Guard had used water cannons against a Philippine supply vessel in the South China Sea. Chinese Defence Ministry spokesman Wu Qian called on Manila to stop violations and provocations near the Second Thomas Shoal, also known as Ren'ai Jiao. He said the incident was caused "exclusively by Philippine provocation," while Chinese actions were "rational, legal, and professional."

The territorial affiliation of some islands and reefs in the South China Sea, including the Philippine-controlled Second Thomas Shoal, has been the subject of disputes between China, the Philippines, and several other Asia-Pacific countries for decades.

(With UNI inputs)