In this June 27, 2008 file image from television, the 60-foot-tall cooling tower at its main reactor complex in Yongbyon North Korea is demolished. AP

A reservoir dam near North Korea's Yongbyon nuclear complex has been breached, a U.S. think tank has said, citing recent satellite imagery.

The reduced water level has left the two pump houses servicing the reactors "high and dry," with the water level above the dam down significantly and the intake cisterns exposed, said 38 North, which specializes in North Korea.

"The inability to maintain a stable reservoir level ... poses a potential problem for continuous reactor operations" if the 5-megawatt nuclear reactor is restarted or the Experimental Light Water Reactor is brought online, 38 North said, citing satellite imagery of Yongbyon complex on Sept. 21.

The complex is home to the 5-megawatt nuclear reactor that was the source of weapons-grade plutonium for North Korea. Pyongyang can harvest one nuclear bomb worth of plutonium by reprocessing spent fuel rods from the reactor.

The U.S. website said there are no observable indications that the 5-megawatt nuclear reactor is operating or that the Experimental Light Water Reactor has been started. (Yonhap)