Simply heartbreaking.

Doctors in the Ukrainian capital Kyiv treating children suffering from cancer have warned that their patients will die if they can't find a way to evacuate. There are currently dozens of children battling cancer sheltering in the basement of Okhmatdyt, Ukraine’s largest children’s hospital as medical professionals and their parents urgently try to continue their treatment. More than 400,000 people in Ukraine have been forced to flee their homes since Russia invaded last week and there has been 352 civilian deaths reported. Speaking with NBC News, Dr Lesia Lysytsia said: "These children suffer more because they need to stay alive to fight with the cancer - and this fight cannot wait. "If the children's cancer treatment is interrupted further by the war, our patients, they will die." Supplies at the hospital are running low as doctors now only have access to a basic form of chemotherapy to treat their patients with. Pictures have emerged of children sheltering in the hospital basement, staying on makeshift beds and wearing face coverings. The doctors here are in a difficult situation as it could be dangerous to move extremely sick children to another area that has more supplies. Lysytsia said that parents have been asking if it's "safe" to leave the basement and are worried they'll be attacked if they leave. For the patients that cannot wait to be evacuated, the hospital is trying to move them to the Western Ukrainian Specialized Children's Medical Center in Lviv, with 14 children already headed there on Tuesday. They will then be sent to Poland to receive more medical care. While Ukrainian cities are under attack, Dr Roman Kizyma, the lead pediatric oncologist at the Western Ukrainian Specialized Children's Medical Center, told MailOnline that Lviv is safer than other cities but sirens can still be heard. Distracting the children from these sirens, doctors have devised the rush to shelters as a game, telling the children to "run to the dungeon."