A Japanese defense report has expressed grave concern over China's declaration of an air defense identification zone over the East China Sea.
The report said the move by Beijing is a dangerous one that is raising tension in the region.
The Defense Ministry report for 2014 also refers to China's increased maritime activities in the East and South China seas.
It said that Beijing is using its military might to try to change the status quo based on its own claims, which are inconsistent with international rules.
The report also warns that China's announced defense spending increased by roughly 40 times over the past 26 years.
The report said Japan is deeply concerned by the announcement of the air defense identification zone, which covers an area that includes the Senkaku Islands.
Japan controls the islands, but China and Taiwan also claim them.
It said the zone unilaterally changed the status quo and could trigger an unexpected incident.