(Bloomberg) -- Russian troops may have withdrawn from northern Ukraine but the land mines they scattered across the area pose a significant problem to a semblance of normal life resuming, according to Kyiv’s mayor.

Vitali Klitschko said the unexploded ordnance is mostly on the outskirts of Kyiv and in smaller towns and on farming land. But, he said, it adds to the concern in the capital that “our city is not safe. Not everyone can feel safe here.”

Klitschko was speaking in an interview on the sidelines of the World Economic Forum in Davos with his brother and fellow world boxing champion Wladimir. The brothers run their own foundation which once focused on promoting sport to Ukraine’s youth, but is now running courses in handling explosives and critical first aid.

“It is a huge issue,” Wladimir said. “Ukraine is probably one of the most dangerous countries regarding the mines and devices that have not exploded during the war. We see daily on the outskirts of the city that people are losing their lives. Daily.”

Russia sowed land mines and booby traps as troops pulled back from some areas, making it harder to resettle parts of the country until the deserted battle zones are painstakingly cleared, according to James Cowan, chief executive officer of the HALO Trust, a humanitarian organization.

The Kyiv city government issued a statement on Monday warning people not to go to certain parks because of the risk from explosives. Ukraine’s state emergency service estimates that 300,000 square kilometers -- half the country -- has unexploded ordnance and will take at least 5 years to clear entirely. That will restrict the ability of both farmers and factories to resume operations.

An explosives sniffer dog called Patron (cartridge in Ukrainian) has become a social media star for his work finding mines. He was recently given an award by President Volodymyr Zelenskiy and is used in promotions warning children not to touch suspicious items.

Wladimir said the brothers’ sports foundation is now also focused on educating children on explosives through both practical and online courses, including first aid -- “teenagers learning if something happens to them how they can stop the bleeding so they should understand they have just minutes if they don’t.”

“This is something that was unimaginable to us as the founders of the Klitschko foundation. Education in sport is one of the cores of the foundation but now we are into an issue like that. First safety and then first aid.”

Ukraine has asked for funds to help to clear land mines from other countries. 

Zelenskiy has said Russia, itself a key agricultural exporter, deliberately targeted farmland, placing mines in fields and destroying equipment and storage facilities. Ukraine is the world’s largest producer of sunflower oil and ranks among the top six exporters of wheat, corn, chicken and honey.

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