The idea of partially classifying Japan's national defense guidelines, under a major policy review into the country's security by year-end, is being floated to better deal with increased regional security threats by China and Russia, government sources said Saturday.

Making the revised version of the National Defense Program Guidelines, a 10-year defense buildup policy, confidential would be in line with the mostly classified U.S. National Defense Strategy and enable Japan to be more specific in its strategy toward contingencies also involving North Korea, the sources said.

Japanese Prime Minister Fumio Kishida takes a ride in a tank during his visit to the Ground Self-Defense Force's Asaka base straddling Tokyo and Saitama Prefecture on Nov. 27, 2021. (Kyodo) ==Kyodo

The guidelines, which are now publicly available, are one of three documents the government is reviewing by the year-end, with focus on the politically sensitive issue of whether Japan can acquire capabilities to attack enemy bases in counterstrike given its exclusively-defense oriented policy under the war-renouncing Constitution.

The two others to be updated are the National Security Strategy and the midterm defense buildup program, which specifies development plans and costs every five years.

The possible move to classify portions of the guidelines follows recommendations by the ruling Liberal Democratic Party as well as by some of the security and diplomacy experts invited to the government's closed-door hearings, bearing in mind the regional security challenges, the sources said.

China has been intensifying its maritime assertiveness in the East and South China seas, including the Japanese-controlled, Chinese-claimed Senkaku Islands, as well as stepping up its military, diplomatic and economic pressure on Taiwan.

Russia, which invaded Ukraine in February, has raised concerns over its unilateral attempts to change the status quo, which could reverberate in Asia amid tensions over Taiwan, a self-ruled democratic island that China regards as its territory.

Concerns also remain high over North Korea's missile and nuclear programs.

The LDP recently proposed to Prime Minister Fumio Kishida, who is party president, that the guidelines be scrapped altogether and a new national defense strategy in sync with the U.S. defense strategy, which has some portions declassified, be drawn up. The party also called for the Self-Defense Forces to develop counterstrike abilities aimed at disabling enemy weapons.

"Having a document similar to the (U.S.) National Defense Strategy is requisite," in strategically dealing with possible contingencies involving China, Russia and North Korea, said an LDP lawmaker well-versed in defense issues.

The U.S. defense strategy was sent to Congress earlier this year and its declassified summary released, whereby Washington says it prioritizes China over Russia as a greater threat to its national security.

Critics, however, fear that it may be hard in the future to review Japan's security strategy, should the guidelines fall under the 2014 secrecy law. The law stipulates that violators will be punished if they leak sensitive information that is designated as a state secret and withheld from the public.