Photos show babies in Ukraine's largest children's hospital being treated in its basement to escape shelling

As Russia's siege of Kyiv continues, the shelling of the city has forced staff of the Okhmatdyt Children's Hospital to move patients into the building's basement.

According to Reuters, the hospital is the largest of its kind in Ukraine and typically handles up to 600 patients, said its chief surgeon Volodymyr Zhovnir on Monday.

However, amid Russia's invasion, the hospital's patient count has dropped to around 200, said Zhovnir, per the wire service.

"These are patients who cannot receive medical treatment at home, they cannot survive without medication, without medical treatment and medical workers," he told Reuters.

According to NBC News, while doctors and nurses continue to administer the limited treatments available to their patients, the hospital also faces a shortage of medicine, food, and water.

Vitaly Demidov, a surgeon at the hospital, told TIME that some patients on oxygen support required ventilators, which were operated by hand when moving them into the basement.

"The saddest thing is that when the siren sounds, we have to go down with the children and parents to the basement," Demidov told the publication. "We run five or six times a day in the basement and back."

Vadym Tkachuk, who heads the intensive care unit of the hospital's Center for Pediatric Cardiology and Cardiac Surgery, told TIME that they have stopped performing surgical procedures unless the conditions are life-threatening.

"Currently, we only perform emergency surgeries on patients who [would] die without cardiac surgery," Tkachuk told publication.

"We have to postpone planned operations until the end of this war."

Some of the hospital's cancer patients have access to only a basic form of chemotherapy since moving to the basement, reported NBC News.

"These children suffer more because they need to stay alive to fight with the cancer — and this fight cannot wait," Dr. Lesia Lysytsia, who works at the hospital, told the outlet.

She noted that the interruption of the patients' other treatments placed them at risk of suffering relapses or falling more ill, per NBC News.

The Guardian reported that the hospital's basement bunker was built in the 1970s to allow treatment to continue amid "potential cold war battles."

While the facility has thick walls, its interiors are basic, with no adult beds, chairs, or tables, per the outlet.

Natalya Tyshchuk, who is staying in the hospital's basement with her infant, told The Guardian: "Conditions are very minimal, but there is a feeling of security here. I sit on the floor, but there are no windows and the walls are thick, and we don't hear any of the explosions except the very loud ones."

TIME reported that the hospital's staff have been singing songs and playing games with their patients to lift their spirits during air raids. Two birthdays have even been celebrated in the basement, per the publication.

A different game is played at Western Ukrainian Specialized Medical Center in Lviv, where some of the Okhmatdyt hospital's more vulnerable patients have been sent, per NBC News.

Roman Kizyma, the Lviv facility's lead pediatric oncologist, told the outlet that patients are made to run into the hospital's basement — called the "dungeon" — each time the air raid sirens sound.

"It is traumatizing," said Kizyma, adding that the game is less effective in distracting older children, who are scared and angry, reported NBC News.