A US think tank says North Korea may have carried out a combustion test of an engine believed to be for a ballistic missile during the past several weeks.
The Center for Strategic and International Studies, or CSIS, announced it reached this conclusion after analyzing satellite photos taken on August 31 of Sohae Satellite Launching Station, at Tongchang-ri in the northwest of North Korea.
The CSIS says ground scarring and burnt vegetation indicate there has probably been an unannounced engine test.
Experts in South Korea say the North likely tested an engine for an intercontinental ballistic missile, or ICBM, or a rocket to carry what it calls a satellite.
North Korean leader Kim Jong Un inspected the Sohae launching station in March.
At the time, he ordered that the facility be refurbished and expanded so that military reconnaissance satellites could be launched from it on large carrier rockets.
North Korea's neighbors are bracing for a possible firing of a long-range ballistic missile that Pyongyang would describe as a satellite launch.