Three Chinese Navy warships sailed through Philippine territory as tensions escalated over the South China Sea.

The Chinese People's Liberation Army (PLA) vessels reportedly violated maritime protocols as they entered Philippine archipelagic waters without proper identification, on February 2.

Footage shows a Philippine Navy ship monitoring the foreign warships - identified as one Renhai Class Cruiser Guided Missile, one Jiankai Class Frigate II, and one Type 903 Fuchi Class Replenishment Oiler - that were travelling through the Mindoro Strait, on February 4.

The Philippine army's Western Mindanao Command said in a statement: 'This is not consistent with the principles of innocent passage which requires continuous and expeditious passage and that the vessel should not linger in archipelagic waters longer than necessary.'

Two Philippine Air Force planes were also deployed to shadow the Chinese vessels, which were believed to be headed to Indonesia to participate in the multinational naval drill 'Exercise Komodo'.

The incident occurred as the Philippine and US Air Forces held joint air patrols and intercept training over parts of the South China Sea on Tuesday.

China has been sending numerous coast guard vessels near the shores of the Philippines on maritime patrol.

One of them is the massive CCG 5901, the world's largest coast guard vessel at 541 feet and 12,000 tons, which started lurking off the seaside province of Zambales on January 4 afternoon.

Authorities believe the ships were deployed to intimidate Filipino fishermen from entering the Scarborough Shoal, a disputed fishing ground and resource-rich area in the South China Sea.

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.