China's state-run media say President Xi Jinping has instructed Communist Party leaders to strengthen defense capabilities for the country's borders, air space and territorial waters.

Xi's remarks came amid China's increasing assertiveness in the East and South China Seas, which is raising tensions with neighboring countries.

China Central Television reported on Wednesday that Xi gave the instruction at a leadership group study session on defense the previous day.

Xi was quoted as telling the meeting that China's border, coastal and air defense is faced with new opportunities and challenges. He reportedly stressed the need for overall planning to improve capabilities for safeguarding the country and protecting its borders.

Xi was also cited as noting that defending China's borders involves multiple entities, including the military and police. He stressed the importance of strengthening the party's intensive guidance on the issue.

China has been adamant in maintaining its territorial claims, and Xi's remarks could lead to a ramping up of the country's maritime activities in the East and South China Seas.

In the East China Sea, Chinese government vessels have repeatedly entered Japanese territorial waters around the Senkaku Islands.

Japan controls the islands. The Japanese government maintains the islands are an inherent part of Japan's territory. China and Taiwan claim them.

China has also been at odds with the Philippines over territorial claims in the South China Sea. Ships from the two sides have had confrontations in recent months.