Videos filmed from China showed an explosion illuminating the sky of a border city in North Korea, believed to be caused by a gas leak that apparently led to a deadly explosion on Monday.

Reuters reported that the videos were published by the Seoul-based Daily NK, which focuses on North Korean affairs, as well as the international news agency Associated Press, while South Korean media reported news about the incident from unnamed sources.

Daily NK quoted a source inside North Korea on Wednesday saying that up to 15 people died in the explosion, which caused a fire in a house in Hyesan, Yanggang Province.

The source added to the newspaper: "The explosion destroyed an entire section of the Harmonica houses. There is nothing of value left inside." Dozens were injured as a result of the explosion.

The Associated Press quoted a travel agent in the Chinese border town of Changbai, who said he witnessed the explosion and filmed a video of it, but did not know the cause.

The videos show a fire glowing above the treetops, punctuated by multiple explosions that caused columns of flame to shoot into the sky. North Korean state media did not mention anything about the incident, and South Korean officials said they could not confirm the reports at this time.