A defense spokesman on Friday warned for "necessary measures" to safeguard its territorial sovereignty and maritime interests as the Philippines steps up provocation in South China Sea with unlawful intrusions.

Ministry of National Defense Spokesman Zhang Xiaogang told a news conference in Beijing that the recent provocation and publicity stunt by the Philippine side violates the guiding principles of the Declaration on the Conduct of Parties in the South China Sea, which China signed along with members of the Association of Southeast Asian Nations in 2002.

Some ill-intentioned countries outside the region also incited the situation.

He said the episode seriously undermines peace and stability in the South China Sea. "We urge the relevant countries to immediately stop their provocative actions and avoid further escalation and deterioration of the situation," Zhang added.

Zhang said that despite repeated warnings from China, the Philippine ships on Dec 10 intruded into waters near Ren'ai Reef in the Nansha Islands to supply an illegally stranded military vessel on Ren'ai Reef.

During this period, the Philippine ships intentionally engaged in dangerous maneuvers and collided with Chinese coast guard ships, resulting in scraping incidents, he said.

Some Philippine military personnel boarded the stranded military vessel hyping up the situation, Zhang added.

The spokesman said that the Chinese coast guard took necessary measures to manage the situation in a professional, restrained, reasonable and lawful manner.

The Chinese military has lodged solemn representations with the Philippine side and expressed strong protest, he said.

"China has indisputable sovereignty over the Nansha Islands, including Ren'ai Reef, and its adjacent waters," he said.