Chinese coast guard personnel aboard smaller rubber boats later deliberately cut the anchor lines of several of the Philippine boats on Friday afternoon off Sabina Shoal, "endangering the vessels and their crews amid strong currents and high waves", the coast guard said.
Chinese officials did not immediately comment on the latest reported flare-up of the long-unresolved territorial disputes in the South China Sea, but they have vowed to defend their claimed territories at all costs.
The South China Sea, a key global trade route, is claimed virtually in its entirety by China despite a 2016 arbitration ruling that declared Beijing's expansive claim invalid based on the 1982 United Nations Convention on the Law of the Sea.
China dismissed the ruling as a sham and continues to defy it.
Two Philippine coast guard ships were deployed to help the Filipinos off Sabina but faced dangerous blocking manoeuvres by the Chinese coast guard.
One of the Chinese ships approached as close as 30 metres to one of the Philippine ships at night-time, Philippine coast guard spokesman Commodore Jay Tarriela said in a news briefing.
"The Chinese coast guard is now targeting ordinary fishermen, ordinary civilians and they are endangering the lives of the Filipino fishermen," Tarriela said.
"Despite these unprofessional and unlawful interferences, the Philippine coast guard successfully reached the fishermen this morning and provided immediate medical attention to the injured along with essential supplies," the Philippine coast guard said on Saturday, suggesting tensions had eased.
The Philippine coast guard called on the Chinese coast guard "to adhere to internationally recognised standards of conduct, prioritising the preservation of life at sea over pretensions of law enforcement that jeopardise the lives of innocent fishermen".
The United States has no claims in the South China Sea but it has repeatedly warned that it is obliged to defend the Philippines, its oldest treaty ally in Asia, if Filipino forces, including coast guard personnel, ships and aircraft come under an armed attack including in the disputed waters.
Vietnam, Malaysia, Brunei and Taiwan are also involved in the territorial disputes, long considered an Asian flashpoint.
