The story of 11-year-old Ukranian boy Hasan leaving his widowed mother to travel 600 miles to Slovakia by himself shines a light on the impact of war on children.

As reported in British tabloid The Sun on Tuesday, the 11-year-old had a passport and a number scribbled on his hand which the Slovak authorities called. It turned out to be his relatives who came to collect him.

Slovak authorities posted images of the boy on their Facebook page and issued a statement praising Hasan's “smile, fearlessness and determination”.

“The whole world has been touched by the story of this 11-year-old boy," they wrote on Facebook. ““He is the biggest hero. With one plastic bag, a passport and a telephone number written on his hand, he came all alone because his mum had to stay."

A video later emerged of the boy's mother Julia Pisecka thanking the Slovak authorities for taking care of Hasan.

The family lives in Zaporizhzhia which is home to a nearby power plant, attacked by the Russians on Monday sparking fears of radiation threats.

The widow said she had to send Hasan away by himself as she had to stay behind to take care of her ailing mother who can't move.

In the video, Pisecka thanks Slovakia's authorities for caring for Hasan and says “People with a big heart live in your small country.”

Eduard Filo of a Christian organization which has helped Hasan and his family safely move to the border said: “We’re looking for ways to get his mum and his disabled grandmother to safety. Hasan and his siblings are safe in Slovakia." ' The UN has described the refugee crisis as the fastest spreading one since World War II.

It also estimates that at least 1.2 million refugees have fled Ukraine since the Russians invaded. Most have fled to Poland while others have gone to Hungary, Slovakia, Moldova, and Romania.