WEST PHILIPPINE SEA (Aboard BRP Gregorio del Pilar)—The Philippines and the United States have expressed concern about the presence of Chinese vessels in the West Philippine Sea while their bilateral maritime cooperative activity was ongoing.

This, according to Vice Admiral Alberto Carlos, chief of Armed Forces of the Philippines-Western Command, to reporters on board the BRP Gregorio del Pilar who were covering the recently concluded Philippines-US joint maritime air exercises in the waters off Lubang, Occidental Mindoro.

"Both of us expressed concern about the presence of the Chinese vessels when we were doing the MCA. But we both agreed that it was a freedom of navigation under the UNCLOS (United Nations Convention of Law of the Sea). They also had the right, and they also enjoyed that right to do that in our EEZ," Carlos said.

"Both of us were concerned when the Chinese declared that they were operating within their jurisdictional area," he added.

While sailing in a portion of the WPS heading to an operational exercise area near Lubang, at least two Chinese vessels operated by the People's Liberation Army Navy consistently shadowed the Philippine ships involved in maritime air drills with the US.

In one incident, a PLAN ship tried to come much closer to the Gregorio del Pilar while shadowing the Philippine ships. The Chinese navy repeatedly told the Philippine crew aboard the Del Pilar that they "should maintain a safe distance."

During the exchange of radio challenges, the Chinese said they were operating in their "jurisdictional area."

Beijing's jurisdictional claims over the area overlap the Philippines' sovereign rights in its exclusive economic zone in the WPS.

Carlos said the AFP-WESCOM would consolidate its reports on China's presence during the MCA at the military general headquarters in Camp Aguinaldo.

"We will submit the reports, necessary reports to higher headquarters. They will assess our reports to see if they will merit the filing of a diplomatic protest. It will be up to the higher-ups, they will make the decision in higher headquarters," he added.