SEOUL, South Korea -- The North Korean military, the world's fourth-largest, has bolstered its special-forces units during the past two years and has deployed a new battle tank, called the Storm, while expanding its tank brigades, the South Korean Defense Ministry said on Thursday in its biennial white paper. The report said the North's overall troop strength had remained the same since 2008, when the active-duty force was estimated at 1.1 million. With a population of 24 million, North Korea has by far the world's largest military in per capita terms. In actual numbers of troops, only China, the United States and India are larger. [ABSTRACT FROM PUBLISHER]