SEOUL, South Korea (AP) – A large explosion occurred in the northern part of North Korea on an important anniversary of the communist regime, a South Korean news agency reported Sunday.

The Yonhap news agency, citing an unidentified source in Beijing, said the explosion happened Thursday in Yanggang province near the border with China. The explosion in Kim Hyong Jik county blasted a crater big enough to be noticed by a satellite, the source said.

North Korea was founded Sept. 9, 1948. Leader Kim Jong Il uses the occasion to stage performances and other events to bolster loyalty among the impoverished North Korean population.

Experts have speculated that North Korea might use a major anniversary to conduct a nuclear-related test, though there was no immediate indication that Thursday’s reported explosion was linked to Pyongyang’s efforts to develop nuclear weapons.

That effort has led to six-nation talks aimed at persuading North Korea to abandon its atomic weapons programs.

On April 22, train wagons at a railway station exploded in the North Korean town of Ryongchon, killing 160 people and injuring an estimated 1,300, according to some estimates. The blast was believed to have been sparked by a train laden with oil and chemicals that hit power lines.

The source in the Yonhap report said Thursday’s explosion reportedly was bigger than the train explosion.

AP-ES-09-11-04 2304EDT