Ukraine children's hospital continues to care for patients in basement amid Russia attacks

While more than 1 million people have fled Ukraine since the invasion of Russian forces, some of the country's most vulnerable children have stayed behind.

At Ohmadyt Children's Hospital in Kyiv, pediatric patients are being cared for in the basement of the hospital.

Among the patients is a young boy named Yarik, who is hospitalized due to fluid in his brain.

Another patient, a young girl named Illiya, who is being treated for heart problems, is held by her father, who told ABC News he is caring for her while his wife and their six other children are hiding near the front lines.

The girl's father, Valentine, told ABC News' Ian Pannell the situation is hard, adding, "We do not give up. We fight. We stick to the last, because we cannot do otherwise."

One 2-year-old boy, named David, remains in the hospital because he needs dialysis treatment, while another boy, Vova, 13, was brought to the hospital after being badly injured when his family's car came under attack, the boys' families told ABC News.

Vova's father and cousin were killed in the attack, and now he is fighting for his life in intensive care, according to his mother.

Caring for the young patients are doctors and nurses who are risking their lives, too.

Dr. Oleg Gordyk told ABC News his family is staying with him in the underground clinic.

"This week was very, very terrible for me because my family is staying in our clinic," he said. "My daughter, 17-years-old, now she works as [a] nurse."

Ukraine has been under attack since Feb. 24, when Russian President Vladimir Putin announced a "special military operation."

Russian forces don't appear to have advanced closer to Kyiv since coming within about 20 miles, although smaller advanced groups have been fighting gun battles with Ukrainian forces inside the capital since at least Friday.

Ohmadyt's chief surgeon, Dr. Volodymyr Zhovnir, said Monday he hospital now has around 200 patients, down from its usual of up to 600 patients, according to Reuters.

"These are patients who cannot receive medical treatment at home, they cannot survive without medication, without medical treatment and medical workers," said Zhovnir, adding that the hospital has stockpiled a months' worth of medication but is need of food for newborn babies, according to Reuters.

Gordyk told ABC News that even amid the horrors of war, he sees a sliver of hope.

"I believe in victory," he said. "I believe in maybe, in the future -- tomorrow, maybe next week or next month, I see sun in our clinic."