MANILA, Philippines (AP) -- The Philippine government summoned China's ambassador on Monday and presented a strongly worded diplomatic protest over the Chinese coast guard's use of water cannons in a weekend confrontation with Philippine vessels in the disputed South China Sea, officials said.
The tense hours-long standoff occurred Saturday near Second Thomas Shoal, which has been occupied for decades by Philippine forces stationed onboard a rusting, grounded navy ship but is also claimed by China. It was the latest flareup in long-seething territorial conflicts in the South China Sea involving China, the Philippines, Vietnam, Malaysia, Taiwan and Brunei.
The United States, the European Union, Australia and Japan expressed support to the Philippines and concern over the Chinese actions. Washington renewed a warning that it is obliged to defend its longtime treaty ally if Philippine public vessels and forces come under armed attack, including in the South China Sea.
Philippine coast guard and diplomatic officials held a news conference on Monday at which they showed videos and photographs which they said showed six Chinese coast guard ships and two militia vessels blocking two Philippine navy-chartered civilian boats taking supplies to the Philippine forces at Second Thomas Shoal. One supply boat was hit with a powerful water cannon by the Chinese coast guard, the Philippine military said.
Only one of the two Philippine boats managed to deliver food, water, fuel and other supplies to the Philippine forces guarding the shoal, the officials said.
During the confrontation, two Philippine coast guard ships escorting the supply boats were also blocked by the Chinese coast guard ships at close range and were threatened with water cannons. Three Chinese navy ships stood by at a close distance at one point, Philippine coast guard Commodore Jay Tarriela said.
"This was like a David and Goliath situation," Jonathan Malaya of the National Security Council said.
Malaya emphasized that the Philippines would not withdraw its forces from Second Thomas Shoal.
Department of Foreign Affairs spokesperson Teresita Daza said China's ambassador to Manila, Huang Xilian, was summoned and handed a diplomatic protest by Philippine Undersecretary Theresa Lazaro.
In it, the Philippines told China to stop its illegal actions against Philippine vessels in the South China Sea, stop interfering in legitimate Philippine activities, and abide by international laws, including the 1982 U.N. Convention on the Law of the Seas, Daza said.
In Beijing, the Chinese coast guard acknowledged its ships used water cannons against the Philippine vessels, which it said strayed without authorization into the shoal, which Beijing calls Ren'ai Jiao. It accused the Philippines of reneging on a pledge to remove the grounded Filipino warship from the shoal.
"In order to avoid direct blocking and collisions when repeated warnings were ineffective, water cannons were used as a warning. The on-site operation was professional and restrained, which is beyond reproach," the Chinese coast guard said. "China will continue to take necessary measures to firmly safeguard its territorial sovereignty."
China has long demanded that the Philippines withdraw its naval personnel and tow away the still-commissioned but crumbling ship, the BRP Sierra Madre. The ship was deliberately marooned on the shoal in 1999 and now serves as a fragile symbol of Manila's territorial claim to the atoll.
The disputes in the South China Sea, one of the world's busiest sea lanes, have long been regarded as a potential flashpoint and have become a fault line in the rivalry between the United States and China in the region.
China claims ownership over virtually the entire South China Sea despite an international ruling that invalidated its claims in 2016 by an arbitration tribunal set up under the U.N. Convention on the Law of the Sea. China rejects that ruling and continues to defy it.
The U.S. State Department said in a statement on Sunday that by "firing water cannons and employing unsafe blocking maneuvers, (Chinese) ships interfered with the Philippines' lawful exercise of high seas freedom of navigation and jeopardized the safety of the Philippine vessels and crew." It added that such actions are a direct threat to "regional peace and stability."
While the U.S. lays no claims to the South China Sea, it has often criticized China's aggressive actions and deployed its warships and fighter jets in patrols and military exercises with regional allies to uphold freedom of navigation and overflight, which it says are in America's national interest.
China has told the U.S. to stop meddling in what it calls a purely Asian dispute and has warned of unspecified repercussions.