Japanese Prime Minister Shinzo Abe says his country should boost its military readiness because of what he called "repeated provocations" against Tokyo.
Abe also cited worsening regional security in his comments made Thursday to top defense ministry officials after inspecting Japan's Self-Defense Force troops.
"We cannot look away from the reality of repeated provocations against our sovereignty, of the worsening safety and security situation surrounding our nation. We must not conclude with a mere pretense that diverges from reality and thereby put strain on the self-defense forces that are on the ground," he said.
Japan and China are in a dispute over a group of islands in a part of the East China Sea that is claimed by both countries. Increased Chinese and Japanese air and sea patrols there have some concerned about a military clash.
Beijing has been angered by Mr. Abe's firm stance on the island issue. It has also expressed concern at Abe's past calls for changes to Japan's pacifist constitution that was drafted by the United States following World War Two.
In his speech Thursday, Abe said Japan's current alliance with Washington has been beneficial, but that additional steps need to be taken to make sure Japan can protect itself in the future.
"We have continually walked the road of peace for 68 years after the end of the second world war, with the U.S. security alliance as our bedrock. We can be proud of that. But this will not guarantee future peace," he said.
After losing in World War II, occupied Japan was forced to dismantle its military and adopt a constitution that allows the use of arms only in case of an attack on its territory.
Interpretations of the constitution have since been stretched so as to allow Japan's Self-Defense Forces to be strengthened over the years along with the growth of Tokyo's economic power.