The Chinese Coast Guard (CCG) aggressively flashed an LED warning sign as they blocked a Philippine vessel from entering disputed waters.

Footage shows the China Coast Guard Vessel 3105 appearing to block a ship from the Philippine Bureau of Fisheries and Aquatic Resources (BFAR) travelling to the contested Scarborough Shoal, or Hunagyan Island, on September 22.

The message read: 'This is China Coast Guard Vessel 3105. Huangyan Island has been China's inherent territory since ancient times. Your vessel has entered the sea area under the jurisdiction of the People's Republic of China without permission, threatening the safety of our islands and reefs. Please leave immediately.'

The incident comes amid recent mounting tensions over the resource-rich area in the South China Sea.

In a statement on September 24, the Philippine Coast Guard said the CCG has installed a 'floating barrier' approximately 300 metres long, preventing Filipino fishermen from trawling in the region. The barrier was discovered during a routine patrol on September 22.

The PCG said: 'It was reported by the Filipino fishermen that the CCG vessels usually install floating barriers whenever they monitor a large number of Filipino fishermen in the area.

'During the routine maritime patrol, the BFAR vessel observed more than fifty (50) Filipino fishing boats engaged in fishing activities in the area.'

The BFAR ship was en route to provide supplies to the fishermen when it was blocked by the CCG vessel. It reportedly responded to all of the radio calls sent out by the CCG crew.

The PCG said it 'will continue to work closely with all concerned government agencies to address these challenges, uphold our maritime rights and protect our maritime domains.'

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.