Two members of Kuwait's so-called "stateless" community say the Islamic State militant known as "Jihadi John" was born to an undocumented family in an impoverished corner of the oil-rich nation.

They told The Associated Press on Monday that family members of militant Mohammed Emwazi in the Gulf nation have been instructed by authorities not to speak to the media.

Emwazi left Kuwait for Britain when he was only a boy. A family acquaintance described him as a polite young man, almost timid in nature. He agreed to be identified only by his first name of Tareq, fearing government retribution.

He and activist for stateless rights Abdul Hakeem Al-Fadhli said the family lived in the run-down Taima area of Jahra, a city on the outskirts of Kuwait City.