At many as 3,000 people are reported dead or injured in a explosion after two fuel trains collided at a North Korean railway station, report agencies.

"We've obtained the information that there was a large explosion near Ryongchon Station," Yonhap quoted a South Korean defense ministry official as saying.  "We have yet to find out the cause of the incident, the kind of explosion and how many died."

Quoting sources in the Chinese city of Dandong, which borders North Korea, Yonhap said  the trains carrying oil, gasoline and liquefied petroleum gas collided at Ryonchon station, about 50 km from the border city of Sinuiju.

"The area around Ryongchon station has turned into ruins as if it were bombarded," it quoted witnesses as saying. "Debris from the explosion soared high into the sky and drifted to Sinuiju," a North Korean town on the border with China.

North Korean leader Kim Jong II's  special train had passed through the town nine hours earlier, Yonhap said. He was returning from talks with the Chinese leadership in Beijing.  

South Korean news channel YTN said the causalities included Chinese living in the North Korean border region, and some of the injured were evacuated to hospitals in Dandong, China.