BEIJING - China's Defense Ministry on Thursday said the Chinese military "closely monitors" and is "highly vigilant" concerning relevant Japanese Air Self-Defense Force activity in the airspace over the Diaoyu Islands.

Ministry of Defense spokesman Yang Yujun made the remarks at a press briefing while commenting on Japanese fighter jets' recent interception of a Chinese marine surveillance plane patrolling areas around the Diaoyu Islands.

"We will decisively fulfill our tasks and missions while coordinating with relevant departments such as maritime supervision organs, so as to safeguard China's maritime law enforcement activities and protect the country's territorial integrity and maritime rights," Yang said.

Yang said it is "justifiable" for the Chinese military to provide security in waters under China's jurisdiction, and other countries are "in no position" to make irresponsible remarks in this regard.

"China-Japan defense relations are an important and sensitive part of bilateral ties, and the Japanese side should face up to the difficulties and problems that currently exist in bilateral ties," Yang said.

He also called on Japan to take concrete steps to properly handle relevant issues and maintain the overall situation of Sino-Japanese ties.

Media reports say Japan's Air Self-Defense Force sent F-15 fighter jets to the area on Saturday to intercept a Chinese marine surveillance plane bound for the Diaoyu Islands in the East China Sea.