The latest South China Sea clash saw China’s coast guard wielding axes and a Philippine sailor lose his thumb in an escalation that underscored Beijing’s willingness to see how far it can push Manila — and its allies in Washington.

The Philippines Armed Forces called the June 17 moves by China — which included hurling rocks and using knives to puncture an inflatable craft trying to resupply its forces — a "brutal assault" and said the Chinese sailors acted like pirates. The U.S. State Department said China’s actions were "reckless" and threatened regional peace and stability.

But that was as far as the public response went, with neither the Philippines nor Washington seeking to exacerbate a crisis that has been building for years.