MANILA, Philippines (AP) — The Philippine national police chief says the government will investigate 11 Chinese fishermen to see if they illegally entered the country or committed other crimes, ignoring China’s demand for them to be immediately released.

China pressed the Philippines to release the fishermen and their boat, warning Manila Thursday not to take any more “provocative actions so as to avoid further damage to the bilateral relations.”

Asked if the Philippines will heed China’s demand, national police chief Alan Purisima says the fishermen will be investigated to determine if they illegally entered the country and committed other crimes such as poaching.

Philippine police took the fishermen and their boat into custody Tuesday in a disputed South China Sea shoal, adding the vessel was loaded with more than 350 endangered green sea turtle.