Feb. 13 (UPI) -- South Korea says the missile North Korea tested Sunday is an upgraded version of a submarine-launched ballistic missile the regime fired last August.
North Korea made the identical claim, and said the SLBM KN-11, also known as the Pukguksong-1, or Polaris-1, was the base model for the latest launch, South Korean newspaper Hankyoreh reported Monday.
The Sunday launch of the Pukguksong-2 was prominently displayed on the pages of the Workers' Party newspaper Rodong Sinmun on Monday.
But immediately after reports of the launch, evaluations of the rocket have diverged across different government agencies in Seoul.
South Korea's military said Sunday the rocket is a "new solid-propulsion long-range missile," and later on Monday Seoul's joint chiefs said the "Pukguksong-2 appears to be a solid-fuel driven midrange ballistic missile," or IRBM.
Military authorities in Seoul now believe the missile is an improved version of the Pukguksong-1, North Korea's SLBM, News 1 reported.
A joint chief official who spoke to the news service on the condition of anonymity said the military is investigating whether North Korea is in the midst of developing a ground-to-ground ballistic missile capability for its SLBM.
But the Seoul official said it is not possible at this point to conclude whether the Pukguksong-1 is capable of being mounted with a miniaturized nuclear warhead.
"We cannot make a judgment on the extent and nature of North Korea propaganda that claims it has miniaturized nuclear warheads," the official said.
Chae Yeon-seok, a scientist at Korea University of Science and Technology in Daejeon, confirmed that the missile launched on Sunday was not strikingly different from the Pukguksong-1.
"Basically, the technology of the two [missiles] is the same," Chae told Yonhap.
South Korean Defense Minister Han Min-koo issued a strong response to the launch on Monday, and requested the country's 13th Air Operations Command to check for military preparedness.
North Korea claimed Sunday the anti-missile defense system THAAD and South Korea's "Kill Chain" strategy to destroy and detect missiles will not defend against its projectiles.