A large explosion occurred near a train station in the northwest of the Democratic People's Republic of Korea (DPRK) on Thursday afternoon, killing or injuring up to 3,000 people, South Korean officials said Friday.

"We've obtained the information that there was a large explosion near Ryongchon Station," a defense ministry official told the Yohap news agency. "We have yet to find out the cause of the incident, the kind of explosion and how many died."

The entire area "was turned into ruins comparable to the aftermath of a massive bombing," witnesses were quoted as saying.

The accident occurred when two trains carrying oil and liquefied petroleum gas collided and exploded in Ryongchon, a townabout 50 km north of Pyongyang.

DPRK authorities declared a state of emergency in the area after the explosion, and the investigation of the cause is underway, Yonhap said.