The Japanese Defense Ministry on Thursday requested a record-high budget of 5.26 trillion yen ($47.8 billion) for fiscal 2018 as it seeks to counter missile threats from North Korea and defend remote islands in southwestern Japan in light of China's rising maritime assertiveness.

The requested sum marks a 2.5 percent increase from the initial budget for the current year through March. Japan's defense budget has been on the rise under Prime Minister Shinzo Abe, who wants Japan to play a more active role in security issues, having topped 5 trillion yen in fiscal 2017 for a second-straight year.

The ministry said in the request that it is aiming to seek funds to introduce a new missile shield system, possibly the land-based Aegis Ashore, while leaving open the actual sum. Details are expected to be fleshed out before the government finishes drawing up the fiscal 2018 budget plan by the end of the year.

Currently, the Maritime Self-Defense Force's destroyers, equipped with the Aegis combat system and Standard Missile-3 interceptors, are tasked with stopping missiles in the outer atmosphere. If they fail, the Air Self-Defense Force's ground-based Patriot Advanced Capability-3 interceptors will counter the attack in the lower tier.

Aegis Ashore uses similar components to those fitted on MSDF Aegis destroyers, but is expected to reduce the workload of the Japanese Self-Defense Forces members in missile intercept operations because the system will be permanently installed on land.

Experts say around two Aegis Ashore units will be enough to cover the entire landmass of Japan, each costing about 80 billion. The system is made by Lockheed Martin Corp.

To improve the defense capabilities of existing systems, the ministry asked for 47.2 billion yen and 20.5 billion yen, respectively, to acquire more capable interceptor missiles known as SM-3 Block 2A and PAC-3 MSE.

The current PAC-3 batteries deployed nationwide have a range of several dozen kilometers, but the use of PAC-3 MSE missiles is expected to double the range of defense.

About 10.7 billion yen is eyed to upgrade Japan's air defense command and control system so that it can be better prepared for missiles launched simultaneously or on a highly "lofted" trajectory, a method North Korea has recently tested when firing missiles.

The ministry also sought 19.6 billion yen as costs to work toward the development of a new radar system with improved abilities to detect and track ballistic missiles, which is called Multi-Input Multi-Output, or MIMO.

Ahead of the planned deployment of Ground Self-Defense Force units tasked to guard Japan's far-flung islands, the ministry sought 55.2 billion yen that includes outlays to build barracks and other facilities on Miyako Island and Amami-Oshima Island, located southwest and northeast of Okinawa's main island, respectively.

The ministry also said it wants to set aside 10 billion yen to study technologies to create high-speed glide bombs, a longer-range weapon which it says would be useful for operations to retake invaded remote islands.

Another 7.7 billion yen is also requested for research on anti-ship missiles also for the purpose of island defense.

The ministry also asked for 88.1 billion yen to acquire six F-35 stealth fighter jets and 45.7 billion yen for four Osprey tilt-rotor transport aircraft.

With Japan and the United States using satellites to check on missile threats and other purposes, the ministry demanded 4.4 billion yen to design a space observation system that would protect the satellites from harmful space debris and other satellites.

The budget request was worked out by setting the dollar's exchange rate at 110 yen for the next fiscal year, the ministry said.