A Philippine Coast Guard (PCG) aircraft shadowed a Chinese research vessel sailing in Philippine territory.

Footage shows the PCG Islander 4177 hovering over China's 114-metre Zhong Shan Da Xue lurking 80 miles northeast of Batanes island, on April 15.

Despite repeated radio challenges from the aircraft, the Chinese crew reportedly ignored warnings and continued sailing in Philippine territorial waters.

In a statement, PCG spokesman Commodore Jay Tarriela said: 'The crew of the PCG Islander attempted to establish radio communication with the vessel multiple times, but there was no response.

'PCG aviators underscored on their radio challenge that the said Chinese vessel lacks the authority to conduct marine scientific research within the Exclusive Economic Zone (EEZ) of the Philippines, emphasizing that its activities constitute a clear violation of the United Nations Convention on the Law of the Sea (UNCLOS) and the Philippine Maritime Zones Act.'

The same Chinese vessel was flagged just a week earlier loitering in the same area.

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.