The Philippines is the country that undermines stability and causes trouble in the South China Sea, a Chinese defense spokesman said on Thursday.

Senior Colonel Zhang Xiaogang made the remark in a regular news briefing in Beijing, in response to a media report that the Philippines and Australia recently conducted a joint military exercise in the Southeast Asian country. According to the Associated Press, military personnel from the United States, Canada, Japan and other countries joined the exercise as observers.

In addition, the Philippines and Australia recently held a defense ministers' meeting, where the Philippines expressed grave concerns over China's actions in the South China Sea, according to AP.

Zhang, while stressing that the South China Sea should be an area of peace, cooperation and friendship, said the Philippine side has repeatedly courted influence from outside powers to cause disruption and, in the process, has jeopardized regional security and stability.

"Reality has proven time and again that the Philippine side is the one who undermines stability and causes trouble in the South China Sea," he said.

"At the same time, certain external countries have instigated and supported the Philippines in taking irresponsible actions that harm the shared interests of regional countries," Zhang added.

China's actions in safeguarding its territorial sovereignty and maritime rights and interests are justified and legitimate, he said.

"We will take firm countermeasures against any provocative behaviors," Zhang warned.