North Korean authorities are investigating recent fires at an arms factory and a train transporting military goods, sources said Monday.

They said a huge fire broke out early this month on a train carrying military uniforms in Ryanggang Province, which is home to the North's armaments industry, causing considerable losses.

In September, a fire broke out in an arms factory in North Pyongan Province. Both happened near the border with China.

One source said it remains unclear what caused the fires and whether they are related, but they could have been the result of minor resistance to the regime of Kim Jong-un.

The regime still has a firm grip on officials, soldiers and the public at large, making it extremely difficult to organize any major resistance. But sources say disgruntled citizens may be venting their frustration with arson targeting key facilities.

Since Kim came to power in 2012, new high rises, water park and other leisure facilities have mushroomed in the capital Pyongyang, but people in rural areas are growing increasingly disgruntled with their poor living conditions.

