The North Korean Army's Guard Command, a military unit tasked with protecting leader Kim Jong-il, is hiding scores of tanks in Pyongyang to quell any popular uprising, Radio Free Asia claimed Tuesday.

The U.S.-funded radio station quoted a defector from Pyongyang as saying, "There is a battalion of about 50 tanks from the Guard Command in the Taedong River area in eastern Pyongyang. They stage a field exercise about once a year."

He said the tanks used to move only at the night to escape public notice. "All are hidden underground. I heard from families of officers of the tank battalion that there are also tanks in an underground near Moranbong," a hill in downtown Pyongyang.

Kim Kwang-jin, another defector who works for the U.S. Committee for Human Rights in North Korea, said there used to be a battalion of tanks in an underground area beneath the Kumsusan Assembly Hall while Kim Il-sung was alive, but he was unsure whether it is still there.

The tanks are ready to move in respons e to riots or demonstrations, the radio station speculated.

Jong Su-chol (45), a former North Korean Army officer, said, "Major weapons and elite troops of the Guard Command are deployed in Pyongyang. The command is also armed with missiles."

The guard is reportedly so well equipped and trained that it could immediately put down a military coup.