"The latest NPR appears to place emphasis on strengthening nuclear deterrence to protect its mainland and allies in response to a changed global security environment, including growing threats from North Korea," the official said on condition of anonymity.

"Our government evaluates that the review has reaffirmed (Washington's) pledge to provide extended deterrence to South Korea and other allies. South Korea and the US will continue to cooperate in enhancing the promised extended deterrence."

As for the pursuit of low-yield nuclear warheads, the official said it appears that the US is considering the option as part of efforts to enhance its overall nuclear deterrence capability.

As for concerns that the latest NPR has made it easier for the US to use nuclear weapons first, he noted the US sticks to its longtime stance to use its nuclear weapons only when it is deemed necessary to protect the "vital" interests of the US and its allies, which he said was also made clear in the previous review announced eight years ago. (Yonhap)