MANILA, Philippines — The United States on Friday renewed its call on China to stop its aggressive actions in the South China Sea, saying a broader web of security alliances has emerged to preserve the rule of law in the disputed waters.

Washington’s top diplomat in Manila was joined by counterparts from key Western and Asian allies, including Japan and Australia, in a Manila forum to express alarm over increasing hostilities in the contested waters, particularly between China and the Philippines. They committed to help defend a rules-based order in the Indo-Pacific region.

In the worst confrontation so far, Chinese coast guard personnel armed with knives, spears and an axe aboard motorboats repeatedly rammed and destroyed two Philippine navy supply vessels on June 17 in a chaotic faceoff at the disputed Second Thomas Shoal that injured Filipino sailors and led to the seizure of seven Philippine navy rifles.

China and the Philippines blamed one another for the incident, the latest in a series of high-seas confrontations since last year. Aside from China and the Philippines, Vietnam, Malaysia, Brunei and Taiwan have been locked in the decades-long territorial conflicts.

“With the backing of an increasingly interconnected latticework of alliances and partnerships, the United States continues to urge the PRC to cease escalatory and dangerous harassment of Philippine vessels lawfully operating in the Philippines’ exclusive economic zone,” U.S. Ambassador MaryKay Carlson told the forum, referring to the People’s Republic of China.

China should “cease interfering with freedom of navigation and overflight of all states lawfully operating in the region,” Carlson said. “The volume of condemnation from the international community is loud and getting louder and it speaks to our common resolve in support of the international rules and norms that benefit us all.”

The Biden administration has been strengthening an arc of security alliances in Asia as a countermeasure against an increasingly assertive China. That has dovetailed with Philippine President Ferdinand Marcos’s efforts to boost his country’s territorial defense.

Beijing has opposed Washington’s alliance-building and has repeatedly vowed to defend its territorial interests at all costs.

The forum marked the anniversary of a 2016 ruling by an arbitration panel in The Hague, Netherlands that invalidated China’s expansive claims in the South China Sea based on the U.N. Convention on the Law of the Sea. Beijing refused to join the Philippine-initiated arbitration, rejected the ruling and continues to defy it.

Dozens of protesters separately held a rally Friday to mark the anniversary of the arbitration ruling in suburban Quezon city, waving small Philippine flags and displaying posters that read: “China out!” and “Long live the arbitral ruling victory.”

Australian Ambassador HK Yu said the June 17 incident at the shoal was “an escalation in a deeply concerning pattern of behavior by China … which threatens lives and creates risks of miscalculation and escalation.”

“The Philippines is not facing this challenge alone,” Yu said. “I can tell you this, you can count on Australia.”

“As allies, partners and friends, we stand united in navigating these uncertain waters and uphold the fundamental principles that safeguard our shared waters,” Ambassador Kazuya Endo of Japan told the forum that was attended by Manila-based diplomats and top Philippine security officials.

Japan, which has its own dispute with China in the East China Sea, has provided patrol ships and a coastal radar system to boost to the Philippines’ ability to defend its territorial interests in the South China Sea.

Philippine national security adviser Eduardo Ano called for international support in pushing for Chinese compliance to the arbitration ruling. Manila, he said, would seek peaceful resolutions to the disputes but “we will continue to stand our ground and push back against coercion, interference, malign influence and other tactics that seeks to jeopardize our security.”