A South Korean television station says up to 3,000 people were killed or injured when two trains loaded with fuel collided and exploded at a North Korean station near the Chinese border.
North Korean officials have not, so far, confirmed the report by South Korean television station YTN. That and other South Korean media reports say the collision occurred in Ryongchon, about 20 kilometers south of the border with China.
Seoul's Yonhap News Agency says North Korea declared a state of emergency in the area after Thursday's incident.
Sources told Yonhap the incident occurred nine hours after North Korean leader Kim Jong-Il passed through the area following talks with Chinese officials in Beijing.
The trains were reportedly carrying petroleum and natural gas when they collided.
In Washington, State Department spokesman Richard Boucher told reporters Thursday the U.S. government does not know enough about the situation to determine whether, or what kind of, U.S. assistance might be warranted.
Some information for this report provided by Reuters and AFP.