The Philippine Coast Guard (PCG) shadowed Chinese ships allegedly lurking in a contested part of the South China Sea.

The PCG tailed the People's Liberation Army (PLA) Navy and its China Coast Guard (CCG) escort some 69 nautical miles off the Philippines' Cabra Island on July 12.

Footage shows crew of the BRP Teresa Magbanua, the largest ship in the PCG's arsenal, sending a radio challenge to the Chinese warship. The CCG ship replied it was 'asserting China's sovereignty and jurisdiction' over the waters.

In a statement on Saturday, July 12, PCG spokesman Commodore Jay Tarriela said: 'As of 1100H today, BRP Teresa Magbanua continues to shadow PLA Navy warship 793 and CCG 4203, which are joined by an additional vessel, PLA Navy warship 164. The movements of these vessels have necessitated several radio challenges from the PCG throughout the day, without response from the PLA Navy warships.

'Additionally, it has been observed that PLA Navy warship 164 is conducting helicopter landing exercises on its flight deck, with continuous activity recorded throughout the morning.'

The PCG said the operations took place within the Philippine Exclusive Economic Zone, urging the Chinese forces to stop the 'unauthorised' patrols in the region.

Expansionist China currently lays claim over almost the entire South China Sea, one of the world's busiest sea lanes. But a United Nations-backed tribunal in 2016 deemed its claims groundless.

The Communist rogue state - accused of genocide for its crimes against the Uyghur population - has been steadily increasing its influence in recent years through investment in developing countries.