Japan stepped up its warning of the acute threat posed by North Korea's weapons program in its annual Defense White Paper released Tuesday. Pyongyang has continued a series of missile and nuclear tests in defiance of UN sanctions, including firing two intercontinental ballistic missiles (ICBMs) last month that landed off Japan's west coast off Hokkaido island.

"Since last year, when it forcibly implemented two nuclear tests and more than 20 ballistic missile launches, the security threats have entered a new stage," the Japanese Defense Ministry said in the 563-page document.

"It is conceivable that North Korea's nuclear weapons program has already considerably advanced and it is possible that North Korea has already achieved the miniaturization of nuclear weapons and has acquired nuclear warheads," it said.

A change in direction

North Korea's latest ICBM test showed that Pyongyang may now be able to reach well beyond Japan and even hit most of the continental United States with its missiles and weapons. The missile in the most recent test was fired at an extremely lofted trajectory, making the full scale of its capabilities difficult to discern.

This growing threat has prompted Japanese municipalities to hold a number of evacuation drills in case of a possible missile attack.

With North Korea pressing on with missile tests, a group of ruling party lawmakers led by Itsunori Onodera, who became defense minister on Thursday, urged Prime Minister Shinzo Abe in March to consider acquiring the capability to hit enemy bases. That would be considered a drastic change in Japan's defense outlook, which is based on its pacifist post-World War II constitution. While the current government has in recent years revised aspects of the constitution and increased its defense budget, Tokyo has not yet gone so far as to acquire bombers or cruise missiles with enough range to strike other countries.

Read more: North Korea crisis: Which country has the strongest military in the region?

China's growing strength

The white paper also highlighted concerns over China's expanding influence in the region, pointing out that the number of Japan's jet scrambles against Chinese aircraft hit a record high in the year to March 2017.

"There is a possibility that their naval activities, as well as air force activities, will pick up pace in the Sea of Japan from now on," the white paper said.

Tokyo's ties with Beijing have been plagued in recent years by the ongoing territorial dispute over a group of uninhabited islands in the East China Sea.

ss/se (AP, Reuters, AFO)