The Philippines summoned China’s envoy on Monday to protest against “aggressive actions” in the South China Sea at the weekend, as Manila’s defense minister dared Beijing to bolster its vast sovereignty claims by taking them to international arbitration.

The foreign ministry accused China’s coastguard of using water cannon against a civilian boat supplying troops on Saturday at the Second Thomas Shoal, which it said damaged the boat and injured some crew, in the latest in a succession of flare-ups in the past year.

“China’s continued interference with the Philippines’ routine and lawful activities in its own exclusive economic zone (EEZ) is unacceptable,” the Philippine foreign ministry said in a statement, which announced the charge d’affaires of the Chinese embassy had been summoned and a diplomatic protest lodged in Beijing.

“It infringes upon the Philippines’ sovereign rights and jurisdiction,” it said, demanding Chinese vessels leave the area.

China’s coastguard said on Saturday it took necessary measures against Philippine vessels that were intruding in its waters.

China claims almost the entire South China Sea as its own, including the Second Thomas Shoal, which is within the Philippines’ 200 mile EEZ.

The Philippines intentionally grounded an old warship at the shoal in 1999, as a means of bolstering its territorial claims and has kept a small contingent of military there ever since.

China has deployed hundreds of coastguard vessel throughout the South China Sea to patrol what it considers its waters, despite a 2016 Permanent Court of Arbitration ruling in a case brought by Manila that said the claim had no basis under international law. China has refused to recognize that outcome.

Philippine security chiefs convened a high-level meeting on Monday over the incident, to prepare recommendations to put to President Ferdinand Marcos Jr on ways forward in the dispute.

“The Philippines has made sincere efforts to implement the instruction of President Marcos and President Xi to lower tensions,” Manila’s foreign ministry added.

“China’s aggressive actions call into question its sincerity in lowering the tensions and promoting peace.”

China’s defense ministry told the Philippines to cease “provocative actions” and comments that may lead to conflict and an escalation.

Since taking power in 2022, Marcos has taken a tough line against what he sees as Chinese hostility and has refused to cave in to Beijing’s pressure to steer clear of features it claims.

The tensions come at a time when Marcos is seeking to deepen engagement with defense treaty ally the United States, including increasing base access for U.S. troops and expanding military exercises to include joint air and sea patrols, developments China has viewed with suspicion.

In comments likely to rile Beijing, Philippine Defense Secretary Gilberto Teodoro suggested on Monday that China should show the strength of its maritime claims through arbitration, rather than ambiguity.

“If China is not afraid to state its claims to the world, then why don’t we arbitrate under international law?” Philippines’ Teodoro told reporters.

“No country believes (their claims) and they see this as their way to use force, intimidate and bend the Philippines to their ambitions.”