The U.S. Congressional Research Service says North Korea could be facing its biggest test yet when it comes to maintaining its regime.

In a report released late last month, the service said the regime of ailing North Korean leader Kim Jong-il has undergone serious levels of strain as of late due to civic unrest that has resulted from a host of international sanctions, a botched currency reform, an expected leadership succession and the sinking of South Korea’s “Cheonan” naval vessel.

The report expressed concern that Pyongyang, pressed by its dire financial situation, could seek to sell its nuclear technology to rogue nations.

On the sinking of the South Korean warship, the report said the incident could lead to a reconsideration of plans between South Korea and the U.S., including the 2012 scheduled return of wartime operational command to Seoul.