The Self-Defense Forces will closely monitor Chinese activity in the neighboring East China Sea after an international court rules on Beijing's territorial claims in the South China Sea, the defense minister said Tuesday.

"We urge all parties concerned to react in a way that does not raise tensions," Defense Minister Gen Nakatani told a briefing in Tokyo. "We will keep a close watch on the situation in the East China Sea," he added.

The Hague-based Permanent Court of Arbitration has said it will deliver its verdict on a dispute between China and the Philippines over the South China Sea later on Tuesday.

Beijing has said it will ignore the court's decision. Japan and the United States are concerned tension will spike in the region as China reacts to the ruling.

U.S. officials have said say they fear China may declare an air defense identification zone in the South China Sea, as it did in the East China Sea in 2013, or step up its building and fortification of artificial islands.

Tokyo, however, is more worried China will also take action in the neighboring East China Sea where Asia's two biggest economies are locked in a separate territorial dispute.