North Korea is believed to have completed the construction of a second long-range missile launchpad facility.
The facility at Tongchang-ri is more sophisticated than the first facility and is equipped with a 100ft launch tower on the country's north-west border with China, Reuters reports image analyst Tim Brown as saying.
The site is considered key to North Korea's desire to build a missile capable of delivering a nuclear weapon across the Pacific.
The country is also developing the Taepodong-2 missile, with an estimated range of 6,700km, whose production is still underway.
The North Korea's arsenal includes intermediate-range missiles that can hit targets up to 3,000km away.