Manila and Beijing traded accusations about a maritime confrontation Wednesday around the disputed Scarborough Shoal, a day after China submitted a chart of the South China Sea feature’s shore to the U.N. to bolster its claim over it.

China has blocked four Philippine vessels that attempted to “intrude into the territorial waters” of the disputed Scarborough Shoal on Wednesday, the country’s coastguard said.

The China Coast Guard fired water cannons and “sideswiped” a government vessel yesterday during a maritime patrol near Scarborough Shoal (Huangyan Island, 黃岩島), the Philippines said yesterday after Beijing said it had “exercised control” over the ship.