China's coastguard boarded one of the Philippine navy's vessels in the South China Sea earlier in the week, in a confrontation in which a sailor was seriously injured, according to the Philippine military.
According to reports, the Chinese coastguard confiscated weapons from the vessel.
On Monday, the Philippine government accused Chinese vessels of ramming and damaging Philippine vessels near the disputed atoll of Second Thomas Shoal.
According to China's coastguard, the reason for the confrontation was that a Philippine vessel in the area had ignored Chinese warnings and therefore "taken control measures".