Two Philippine government vessels illegally entered waters near China's Zhubi and Tiexian reefs in the South China Sea on Wednesday, with one ship colliding with a China Coast Guard vessel, a Chinese official said Thursday.

In a statement, China Coast Guard spokesman Liu Dejun said vessels No 3002 and No 3003 "illegally intruded" into waters near the Zhubi Reef and Tiexian Reef in the Nansha Islands without Beijing's permission.

Personnel from the Philippines "illegally landed" on Tiexian Reef, Liu said. In response, Chinese Coast Guard officers "took control measures" and conducted on-site verification at the reef, he added.

Chinese actions were professional, regular and lawful, he said.

At 9:13 am Wednesday, the Philippine vessel No 3002 "ignored multiple stern warnings" and "dangerously approached" China Coast Guard vessel No 21559, which was conducting routine patrol operations, Liu said. The close contact resulted in a collision.

Liu said the incident was entirely the fault of the Philippine side.

China has "indisputable sovereignty" over the Nansha Islands and adjacent waters, he said, accusing the Philippines of infringing on China's territorial sovereignty and violating the Declaration on the Conduct of Parties in the South China Sea. The move also threatened regional peace and stability, he added.

Liu called on the Philippines to stop what he described as "infringing actions". He said the China Coast Guard would continue law enforcement and patrol activities in areas under Chinese jurisdiction.

At a regular news conference Thursday, Chinese Foreign Ministry spokeswoman Mao Ning said the coast guard consistently acts in accordance with laws and regulations.