The Pentagon said Wednesday North Korea has at least six Hwasong-13 road-mobile long-range missile launchers, as the U.S. updated the assessment of the secretive nation's military power.

   It said the Hwasong-13 intercontinental ballistic missiles (ICBMs) have a range of more than 3,400 miles, but its capability has yet to be tested.

   The Hwasong-13 has not been flight-tested and "their current reliability as weapon systems would be low," the Pentagon said in its annual report, titled "Military and Security Developments involving the Democratic People's Republic of Korea 2013."

   In the previous version, the U.S. Department of Defense did not mention the Hwasong-13, but said the launchers of the Taepodong-2 long-range missiles have "not yet deployed."

   In this year's document, the department noted launches of the

Taepodong-2 have been observed from both east and west coast launch facilities.

   The Pentagon stressed the communist country remains "one of the United States' most critical security challenges for many reasons."

   These include North Korea's willingness to undertake provocative and destabilizing behavior, including attacks on South Korea, it said.

   The report also carried the U.S. military's formal view on the recent purge and execution of Jang Song-thaek, who was once the No. 2 leader in the North.

   Jang's death is unlikely to lead to major changes in defense policy or internal stability in the near term, the Pentagon said.

   "His absence will most likely be felt in the economy," as Jang was in charge of several high-profile initiatives, particularly with China, to attract foreign currency and investment to the North, it added.

   Jang, the leader Kim Jong-un's uncle, was believed to be a relatively pragmatic advisor to Kim, but his influence probably waned in 2013, the Pentagon said. It cited a significant drop in the number of his public appearances with his nephew.

   Meanwhile, the department maintained its view that North Korea has around 950,000-strong ground forces.

   The number of tanks and armed vehicles increased by 100 each to 4,200 and 2,200 over the past year, it said.  (Yonhap)