SHANGHAI -?Chinese maritime law enforcers recently identified and expelled two Japanese boats that were caught carrying out illegal surveillance activities in China's territorial waters, maritime authorities said Tuesday.

Routine patrols by China Marine Surveillance officers discovered two Japan Coast Guard survey boats in the East China Sea late Sunday. The survey boats left the waters after receiving a warning from the Chinese patrols, according to the State Oceanic Administration (SOA) and China Marine Surveillance.

China Marine Surveillance is a paramilitary maritime law enforcement agency responsible for administering the country's coastal and territorial waters.