China employed what appeared to be a new tactic during its latest clash with the Philippines in the flash point South China Sea, with Manila claiming Chinese vessels had engaged in “dangerous maneuvers,” including attempting to tow one of its ships.

Chinese and Philippine vessels have repeatedly clashed in the South China Sea, particularly near Second Thomas Shoal, a submerged reef claimed by both sides, but controlled by Manila. Vessels from both sides have collided during these clashes numerous times, but any attempt by the Chinese to tow away a Philippine ship could be seen as an escalation on the part of Beijing.

Washington, which has a mutual defense pact with Manila, condemned the “escalatory and irresponsible actions” by China to prevent the Philippines from “lawfully delivering humanitarian supplies” to service members stationed at a Philippine garrison built on a rusting hulk of the BRP Sierra Madre, a warship purposefully grounded on the shoal in 1999.

Chinese “vessels’ dangerous and deliberate use of water cannons, ramming, blocking maneuvers, and towing damaged Philippine vessels, endangered the lives of Philippine service members, is reckless, and threatens regional peace and stability,” U.S. State Department spokesman Matthew Miller said.

Miller also reiterated that the United States remains committed to its 1951 mutual defense treaty, which he said “extends to armed attacks on Philippine armed forces, public vessels, or aircraft — including those of its Coast Guard – anywhere in the South China Sea.”

The Philippine military said Tuesday that one sailor had been seriously injured in the incident, calling the Chinese actions "unacceptable."

"The injured personnel had been safely evacuated and received prompt medical treatment," spokesman Col. Xerxes Trinidad said in a statement.

The military did not offer details of the injuries, but the Philippines' GMA News reported that one solider had his finger cut off and that several others had been hurt. High-powered firearms were also seized and a rigid hull inflatable boat was punctured.

Manila has said that the clash occurred during “a routine rotation and resupply mission” to the garrison, and that Philippine military personnel had shown “restraint and professionalism” and “refrained from escalating" tensions.

The China Coast Guard said earlier Monday that a Philippine supply ship had "deliberately collided” with Chinese vessels, adding that it had taken "control measures” such as warning and interception, boarding and inspection, as well as forced eviction against Philippine vessels "in accordance with the law.”

The waters around Second Thomas Shoal have become a dangerous flash point in the strategic waterway — which Beijing claims in nearly its entirety under its so-called nine-dash line despite overlapping claims by Taiwan, Vietnam, Malaysia, Brunei, Indonesia and the Philippines.

The recent spate of clashes involving the Philippines and China have stoked fears of a miscalculation erupting into a wider clash that draws in the U.S. and others.

Late last month, Philippine President Ferdinand Marcos Jr. laid out a “red line” for Manila, warning Beijing that if a Philippine citizen were to be deliberately killed in a clash, this would be “very close to what we define as an act of war.”

Monday’s confrontation — and the severe injury it involved — was the latest to take the two sides closer to such a scenario.

Beijing has alleged that the Philippines is using the missions to the shoal to bring construction materials to the outpost atop the Sierra Madre in an attempt to make it a permanent facility and cement its claim to the area.

The latest incident also came just days after China Coast Guard regulations allowing it to detain foreign nationals suspected of trespassing in waters it claims for up to 60 days took effect Saturday.

The updated regulations, which were announced last month and expand on China’s 2021 coast guard law, detail procedural guidelines for cracking down on what it defines as illegal activities within “waters under China’s jurisdiction.”

They stipulate that foreign nationals suspected of violating Chinese immigration regulations or “jeopardizing national security interests or undermining public order” in the country’s claimed waters can be detained for 30 days, or up to 60 days in “complicated cases.”

Referencing the new regulations, Beijing’s state-run China Daily newspaper warned Manila in an editorial Monday “that it is playing with fire and risks being burned.”

“Beijing has warned there is a limit to its restraint,” the editorial said.