A 22-year-old woman, who managed to flee North Korea, has warned the western world to be cautious of Kim Jong-un for "he is killing millions of people". Yeonmi Park, now a human rights activist, hails from North Korea's Hyesan city. At present in London, she told the audience at the Women in the World event, to not take their freedom for granted and to take Kim seriously.

"To me it's not a joke. This [the west] is a paradise; it is a heaven," The Guardian quoted Yeonmi as saying. "He is a criminal, he is killing millions there. I hope we see him as not a joke," she said.

She also claimed that the North Korean dictator has complete control over the country. Early on in her childhood she believed that the ruler could read her mind and would "punish her if she had bad thoughts".

Yeonmi told the audience: "I grew up with fear. My mother told me not to whisper because the birds and mice might hear you. Most of all we are hungry, we don't have the luxury of [thinking about] anything else apart from surviving."

Ahead of the 70th anniversary of the Korean Workers' Party, she revealed her life's journey to the audience. Her autobiography was released earlier this month.

Giving further details, she said, when they managed to flee North Korea and cross over to China, her mother was raped and sold for $65 (£42). Later, she was sold as a labourer for $260. When she turned 15, she crossed the Gobi desert in Mongolia to reach South Korea. "When I arrived, everything was shining," she said.

After arriving in South Korea, Yeonmi became a "learning machine".

"I learnt about the universe. I learnt about human rights and human dignity – this was so new to me. Freedom meant for me to wear earrings, not freedom of speech. I don't think I will ever understand what freedom means, but I am enjoying learning," she stressed.