The Philippine Coast Guard vessel, which has been illegally anchored at Xianbin Reef in the South China Sea since April, started moving on Saturday morning but deliberately and dangerously rammed a Chinese Coast Guard ship, a CCG spokesman said on Saturday afternoon.

In a statement, spokesman Liu Dejun said that at 8:02 am on Saturday, the Philippine Coast Guard vessel No 9701, which had been illegally stationed at China's Xianbin Reef, started to move and continued maneuvering provocatively within the lagoon of the reef.

The Chinese Coast Guard vessel No 5205 took measures in accordance with the law, including issuing verbal warnings, monitoring and controlling, the statement said.

At 12:06 pm, the Philippine vessel intentionally collided with the Chinese ship, which was conducting normal law enforcement activities, in an "unprofessional and dangerous manner", causing a scrape, it said, noting that the responsibility lies entirely with the Philippine side.

"We once again urge the Philippine side to face reality, abandon illusions," Liu said. "Immediately withdrawing the vessel on your own is the only correct course of action."

He called on the Philippine side not to misjudge the situation, create hotspots, or escalate the situation.

"Otherwise, the Philippine side will bear all the consequences arising from this," Liu warned.

He emphasized that China has indisputable sovereignty over the Nansha Islands, including Xianbin Reef, and their adjacent waters.

The China Coast Guard will take necessary measures to resolutely thwart any provocations and infringements, and firmly safeguard national territorial sovereignty and maritime rights and interests, the spokesman said.