North Korea’s capability to miniaturize nuclear warheads has reached a “considerable” level, while its long-range missiles are presumed to be capable of reaching the U.S. mainland, according to Seoul’s 2014 defense whitepaper published Tuesday.

The biennial policy paper referred to the North Korean regime and military as “our enemy,” the same term it used in 2010 ― the year the North launched two provocations that killed a total of 50 South Koreans including two civilians.

The paper also reported that the North had established the 12th Corps under the directives of its leader Kim Jong-un to beef up defense around its northwestern province of Chagang-do ― some 60 kilometers from its border with China ― and other areas bordering China and Russia.

On the issue of the territorial row with Japan over South Korea’s easternmost islets of Dokdo, the paper noted the need for a “stern response to some Japanese politicians’ retrogressive historical views and their wrongful claim” to the islets.

It is the first time that Seoul’s whitepaper has mentioned North Korea’s capability to mount nuclear warheads atop ballistic missiles ― an indication that Seoul officially recognizes the North has made strides in developing its nuclear weapons capability through three nuclear tests in 2006, 2009 and 2013.

“If you look at the period of time taken for a nuclear-power state to secure miniaturization capability, it has been about six to seven years,” a senior Defense Ministry official told reporters, declining to be named.

“Eight years have passed by since the North first carried out its nuclear test in 2006, and South Korea and the U.S. alike judge that the North’s miniaturization capability has reached a considerable level.”

The official, however, stressed, “We don’t use any expression indicating that the North currently possesses nuclear weapons in the 2014 whitepaper, meaning that we still do not recognize the North as a nuclear-power state politically and technologically.”

As to the amount of the North’s fissile material, the ministry maintained its previous judgment that the North had some 40 kg of plutonium. To produce one nuclear bomb, around 6 kg of plutonium is required.

The whitepaper also described the North’s ballistic missile capability in greater detail, pointing out, “It is presumed that the North has secured a missile capability to threaten the U.S. mainland through a total of five long-range rocket tests.”

The mention appears to acknowledge that the North’s rocket test in December 2012 was successful. Experts have said that the rocket tested appeared to have a range of some 10,000 km ― far enough to strike the U.S. mainland.

In referring to the North Korean military, the whitepaper retained the term “enemy.” Amid heightened inter-Korean tension in 1995, the paper called the North the main enemy, while in times of relatively stable relations, the tough term was replaced by milder expressions such as “direct military threats.”

According to the paper, the number of North Korean troops increased slightly to 1.2 million from 1.19 million recorded in the 2012 paper, due to an increase of 10,000 Air Force personnel. It has around 1.02 million Army, 120,000 Air Force and 60,000 Navy personnel.

The number of South Korean troops decreased slightly, from 639,000 to 630,000.

The whitepaper also offered a detailed description of the Northern Limit Line as an “effective inter-Korean maritime demarcation line.” “The Republic of Korea and the U.S. urge the North to recognize the effective value of the NLL as we note that it has been an effective means to prevent military tensions for the last 60 years,” the paper said.

By Song Sang-ho (sshluck@heraldcorp.com)