Two Philippine vessels carrying fuel for Filipino fishermen were driven away Thursday at Scarborough Shoal after the Chinese coast guard said they ignored repeated warnings.
Beijing said it used monitoring and blocking measures lawfully, while the Philippine coast guard said a Chinese ship tried to blast one vessel with a water cannon and called the actions illegal and coercive.
Marco Rubio said he raised the latest South China Sea altercation with Chinese Foreign Minister Wang Yi in Manila, calling the incident escalatory and warning any U.S.-China conflict would have global impact.
ASEAN foreign ministers meeting in Manila have focused on South China Sea frictions and other conflicts, while the bloc aims to finish a long-negotiated code of conduct with China this year.