It has been proved time and again that the Philippines is the country that is undermining stability and causing trouble in the South China Sea, a Chinese defense ministry spokesperson said on Thursday.

Zhang Xiaogang, a spokesperson for China's Ministry of National Defense, made the remarks at a press conference, commenting on a recent joint exercise between the Philippines and Australia, and on a joint announcement that the two countries will strengthen their defense cooperation over concerns about "China's actions" in the South China Sea.

The Philippines has repeatedly courted the influence of external powers to make waves in the South China Sea, jeopardizing regional security and stability, Zhang said.

He accused certain countries of instigating and supporting the Philippines' irresponsible actions that harm the shared interests of countries in the region.

Zhang stressed that China's actions to safeguard its territorial sovereignty and maritime rights and interests are justified and legitimate. "We will take firm countermeasures against any provocative behaviors," he said.