Photo/IllutrationAn Aug. 24 file photo provided by the North Korean government shows the test firing of an unspecified missile at an undisclosed location in North Korea. (Korean Central News Agency/Korea News Service via AP)

Japan has raised its caution level about North Korea's missile capability, saying in a defense report that the country resumed missile tests while taking no concrete denuclearization steps and had succeeded in making miniaturized warheads.

The annual defense paper, approved Friday by the Cabinet, underscores Japan's fear of being targeted by its neighbor. Its reaction to the North's recent tests contrasts with a low-key response from the United States.

"Taking into consideration its technological maturity acquired by nuclear tests, North Korea seems to have already achieved miniaturization of warheads to place atop ballistic missiles," said the report, which last year only mentioned it as a possibility.

The North is now aiming to further increase missile ranges, improve accuracy and operational and surprise attack capability and diversify launching methods, it said.

North Korea's military activity "still poses serious and imminent threat" to Japan's security as well as international peace and safety, it said.

Since a second summit between the leaders of the United States and North Korea collapsed without an agreement earlier this year, North Korea has fired 10 short-range missiles and projectiles deemed new and upgraded.

Citing its analysis, the Defense Ministry said they were three new types, including one resembling Russia's Iskander, and flight distances ranged from 200 kilometers to 600 km. It said the missiles were new and their capability upgraded, and that Japan needs to further strengthen its missile defenses.

North Korean missiles with those flight ranges could strike targets in Japan and South Korea but not the United States, which has been the basis for the low-key Trump administration reaction.

"Naturally, we must be fully prepared to defend our country from North Korean missile threats, and we will continue to push forward our preventive measures," Defense Minister Taro Kono said at a news conference Friday.

The defense report also noted China's threat is expanding into space from the regional seas, and said Japan must prioritize space security. China was mentioned as a second significant nation after the United States, the ally and most important nation for Japan.

"China, whose defense budget has been rapidly on the rise, now is almost neck to neck with the United States, becoming major powers in the area of defense," Kono said.

Defense officials have said threats from North Korea and China's assertiveness mean Japan needs higher deterrence and increased missile defense and fighter capability, including cruise missiles and aircraft carriers. Opponents question if Japan, whose pacifist Constitution strictly limits the use of force to self-defense, really needs such high-capability arsenals.

Under the ongoing defense guidelines adopted in December, Japan has been bolstering its defense role under its alliance with the United States and is now launching a space unit and measures against cyber and electromagnetic attacks. Japan needs to be well-prepared and to show it can withstand threats, the guidelines say.

While many countries are developing their capabilities to ensure their military superiority, China and Russia have been enhancing capabilities to "impede the U.S. and its allies from using outer space," the latest report said. It said China and Russia are developing missiles and satellites to destroy satellites or interfere with their communication with the ground. "Threats to stable use of the space are intensifying," it said.

Even though Japan and South Korea are U.S. allies who face shared threats, the defense report gave South Korea a relegated position. Their relations deteriorated rapidly since July over wartime history and export controls that spilled over to defense, prompting Seoul to announce in late August it would terminate a bilateral military intelligence pact. In the report, Japan urged Seoul to "wisely respond to secure appropriate cooperation between Japan and South Korea, and among Japan, the U.S. and South Korea."

The intelligence sharing pact had symbolized the countries' three-way security cooperation countering North Korea and China.

Japan's Maritime Self-Defense Force, citing the recent tensions, said it is not inviting South Korea to an international navy review Japan hosts next month.