The Philippines and the United States agreed to maintain their closer ties amid China's worsening illegal and aggressive actions against Filipino vessels in the West Philippine Sea (WPS).

The agreement was made after Armed Forces of the Philippines (AFP) Chief of Staff Romeo Brawner and Chairman of the Joint Chiefs of Staff of the United States military, Gen. Charles Brown, made a phone call on Monday, December 11.

"The two agreed to maintain close coordination amidst worsening illegal activities of the China Coast Guard (CCG) targeting rotation and re-provisioning missions and patrols of Philippine government vessels in the WPS. They also discussed mutual strategic security interests and opportunities for increased military cooperation," AFP public affairs office chief Col. Xerxes Trinidad said in a statement Tuesday.

The appeal was made soon after a series of incidents over the weekend in which the CCG and Chinese Maritime Militia (CMM) engaged in aggressive maneuvers and fired water cannons at Philippine vessels that were conducting their lawful rotation and resupply missions in Ayungin Shoal and Bajo de Masinloc.

At least three Philippine vessels sustained damage during these occurrences.

According to Trinidad, both leaders reaffirmed their support for the mutual defense treaty, a rules-based international order, and their shared vision of an open and free Indo-Pacific region.

They also reaffirmed their commitment to the Philippine-US alliance.