BEIJING (Yonhap News) ― A North Korean train carrying military supplies caught fire early this month, causing “significant damage,” a source with knowledge of the North said Tuesday.

The incident occurred in the North’s Ryanggang province close to the Chinese border, the source said on the condition of anonymity, adding that he could not confirm whether there were any casualties.

“I learned that a military supply train caught fire early this month in Ryanggang Province and it caused significant damage,” the source said.

Last month, an explosion ripped through a munitions factory in North Pyongan province of North Korea, the source said.

It is impossible to obtain confirmation of the two incidents in North Korea, a country that is notoriously reclusive and rarely reports on accidents that occur within its borders.

The source, however, did not rule out the possibility that the two explosions might have been terrorist attacks. “It is difficult to conclude whether the incidents were terrorist attacks or not, but it is also difficult to rule out the possibility,” the source said.

In 2004, a huge explosion at the North’s border train station of Ryongchon reportedly killed or injured thousands of people.

The deadly blast took place several hours after then North Korean leader Kim Jong-il passed through the railway station, fueling suspicions that the incident may have been an assassination attempt by his opponents.