The U.S. Congressional Research Service says that for the foreseeable future North Korea is expected to maintain a collective leadership system as its state decision-making body.

The U.S. agency said the leadership system appeared after North Korean leader Kim Jong-il was hit by a stroke in August last year and has been in charge ever since.

The increasingly influential system is made up of Kim’s brother-in-law Chang Sung Taek, who runs the North’s secret police, and other senior military officials.

The report omitted North Korea from its list of seven nuclear powers --- including the U.S., Russia and China --- describing North Korea as a country that has only conducted a nuclear test.