North Korea has set up posts along its border with South Korea to be able to more quickly invade its neighbor, while also expanding its artillery and mechanized forces, according to South Korea’s Defense Ministry.

Kim Jong Un’s regime is setting up “infiltration facilities” along the demilitarized zone dividing the countries to be able to both accommodate and rapidly deploy special forces into South Korea if war breaks out, the ministry said in its latest white paper released today. It didn’t say how many posts there are or whether they included tunnels and housed weapons.

North Korea has also probably developed ballistic missiles capable of threatening the continental U.S., according to the report, the first time South Korea has made the assertion in its white paper.

“These are newly spotted structures and could be part of a wider network of military bases and tunnels,” Park Chang Kwon, a senior research fellow at the state-run Korea Institute for Defense Analyses in Seoul, said by phone. South Korea is also “formally saying that North Korea has very much addressed the issues of accuracy and reliability for its intercontinental ballistic missile.”

The biannual assessment offers a glimpse into North Korea’s defense strategy as it develops asymmetric capabilities to defend against the more modern forces across its border. Under its songun, or military-first policy chartered by late leader Kim Jong Il, the North has funneled its limited resources into building weapons systems capable of deterring what it calls U.S. and South Korean hostility.

Miniaturizing Warheads

North Korea’s capacity to miniaturize nuclear warheads is also believed to have reached a “considerable” level, according to the paper. No South Korean or U.S. officials have said the North has yet obtained the ability to tip a long-range missile with a nuclear warhead.

North Korea is also building a fleet of high-speed boats while developing submarines capable of carrying ballistic missiles, according to the white paper.

In his New Year address broadcast Jan. 1, Kim Jong Un said he would beef up his country’s war-fighting forces, which includes the development of nuclear weapons. At the same time, he raised the possibility of a summit with South Korean President Park Geun Hye to ease tensions between the two countries more than 60 years after the end of their civil war.

Nuclear Devices

Park welcomed the call for better ties in her cabinet meeting today and said North Korea should follow through with actions to prove its offer is genuine, according to a statement on her office’s website.

North Korea has 1.2 million troops, a growing arsenal of missiles and has successfully detonated three nuclear devices. It has been developing its longest-range missile, the KN-08, with an estimated reach of 12,000 kilometers (7,458 miles), the ministry said last week in an e-mail.

The country is banned from testing or developing ballistic missiles under sanctions imposed by the United Nations over the nuclear tests it has held since 2006. North Korea and South Korea face each other over one of the world’s most heavily armed borders after their 1950-53 war ended in a truce.