The United Nations children's agency says the conflict in Ukraine has "deeply affected" 580,000 children near the frontlines and in areas of the east not under government control.
As a result, 200,000 youngsters -- more than one-third -- need psycho-social support, UNICEF said on February 19.
"Two years of violence, shelling, and fear have left an indelible mark on thousands of children in eastern Ukraine," said Giovanna Barberis, UNICEF's representative in Ukraine. "As the conflict continues, we need to reach these children urgently to meet their physical as well as psychological needs."
Barberis called on all parties to the conflict "to ensure safe movement and unhindered humanitarian access to help children in need."
UNICEF found that more than 200,000 children have been displaced and at least one in five schools in the conflict zone have been damaged.
Because of destroyed infrastructure and a disrupted healthcare system, Ukraine is facing a polio outbreak, it said.
The agency warned that freezing temperatures and fuel shortages are leaving children at risk of respiratory infections. Moreover, a lack of health services and shortage of medicines threatens to cause more disease outbreaks, it said.