Top military officers of the US and the Philippines have agreed to maintain close cooperation following the firing of water cannons by Chinese vessels against Philippine ships in the South China Sea.

The US Defense Department said the Chairman of the Joint Chiefs of Staff General Charles Q. Brown spoke with the Philippine Chief of Staff of the Armed Forces General Romeo Brawner by phone on Monday.

The two exchanged views on the situation near the Second Thomas Shoal in the Spratly Islands. They also discussed improving information sharing and increasing drills between the two militaries.

On Saturday and Sunday, Chinese vessels fired water cannons at Philippine ships near the Second Thomas Shoal and the Scarborough Shoal. China and the Philippines both claim the area.

Pentagon Press Secretary Pat Ryder told reporters that the Chinese vessels' maneuvers were irresponsible and unsafe. Ryder stressed that the United States' obligations under the mutual defense treaty with the Philippines are ironclad.