Seoul. A North Korean man who has twice fled across the border to China has described to Radio Free Asia (RFA) how he was crammed into a tiny cell with dozens of repatriated defectors, beaten, and nearly starved after Chinese authorities sent him back.

"Each of the detention center cells is about six pyong (about 216 square feet). That's a very small place, where as many as 40 or 50 people are crammed in. It's too narrow and small, and those jailed there can't even put up their feet for sleep so they often have to sleep standing up," the man, who is now again in hiding in China, told RFA's Korean service.

"The only meal they get is tasteless noodle soup served three times daily, which weighs less than 100 grams. I saw some of them dying there. I myself was almost beaten to death by prison guards after having been caught trying to escape," said the man, who spoke on condition of anonymity.

The man described his 50 days in detention in Onsung, North Korea, where he was sent from China's Tumen Detention Center in mid-March this year.

"I was caught fleeing the detention center by security guards, and sent back there, where I had been confined," he said. "The guards there dragged me into a cell like a dog, starting to beat me like hell, often kicking me in the face with iron-heeled military boots. I think five guards beat me for about four hours like that, with an oak stick that was about 6 cms long and 70 cms in length."

"I was beaten all over my body, including my back and face, and finally I lost consciousness after they hit me in the back of my head. I began to regain consciousness after they threw cold water over me, and I found my face was swollen so much that I couldn't see or speak at all."

"I faintly remember a guard officer who looked like a first lieutenant telling his guards to feed me a couple of nutrition pills for fear I might die within a day. He feared they would get punishment if I died. I was given two pills. Even now I just find myself shivering with fear and anger when I think back over what happened to me," the man said.

Human Rights Watch estimates that there could be as many as 300,000 North Koreans hiding in China. There, they risk being picked up by Chinese authorities and returned to North Korea under the terms of a secret 1986 agreement between Beijing and Pyongyang. Under a UN Refugee Convention that China has signed, however, Beijing is required not to send back asylum-seekers in danger of persecution.

When they are sent back to North Korea, defectors face harsh punishments.

Under Article 47 of the Criminal Code of North Korea, any citizen "who defects to a foreign country or to the enemy in betrayal of the country and the people shall be committed to a reform institution for not less than seven years. In cases where the person commits an extremely grave offense, he or she shall be given the death penalty."

Re-education through labor and torture are also commonplace in North Korea's penal system.