Seoul, South Korea (CNN) A North Korean defector has issued an emotional plea to one of the world's most powerful men, China's President Xi Jinping.

"My son is now four, please think of my son as you think of your grandson and take pity on him."

The defector, Mr. Lee, has not seen his 4-year-old son since he was was detained by Chinese authorities, along with his mother -- Lee's wife, on November 4, while attempting to flee from North Korea.

"My son is only four so he probably doesn't understand what a jail is. Why is he in a cold room, what guilt does he carry to have been put in a cold jail cell? I'm angry at the world," said Lee.

To protect the family, CNN is using the pseudonym Mr. Lee, and is blurring the faces of the family in photographs.

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