The United Nations reports Russia has destroyed 50% of Ukraine’s energy infrastructure, putting millions of people at risk of sickness and death as temperatures continue to plunge.

Regular blackouts and power cuts are affecting just about everyone in Ukraine. The U.N., however, reports the situation is particularly catastrophic for more than 10 million people living near the front line. The U.N. says they are in the greatest need of assistance, and are facing winter without water, heat and electricity.

Jaco Cilliers, the resident representative to Ukraine for the U.N. Development Program, said helping people stay warm during winter will be a central part of the U.N.’s role over the coming months.

“How to keep, for instance, just powers on in the hospitals, in schools, in community centers. Keeping people warm is a matter of life and death at the moment. And it is really a great concern that so many people are vulnerable in the current situation,” Cilliers said. “It is estimated that nearly 18 million people, or 40% of Ukraine’s population, will need some sort of humanitarian aid during these periods of time.”

Cilliers said Ukrainian President Volodymyr Zelenskyy has asked the UNDP and World Bank to do a needs and damage assessment of the infrastructure around the energy grid. The initial report is expected to be ready by the end of January, and is to be updated every two months going forward.

In the meantime, Cilliers said the UNDP is providing emergency support and services to help Ukrainians, and is supporting the state emergency services by providing new equipment such as ambulances and generators.

The UNDP representative noted that conditions are particularly desperate for vulnerable people, such as the elderly and those living close to the war zones where water and electricity have been cut off.

“What is being created is — there are both shelters created for people where they can come and get emergency support. They can get blankets. They can get heating equipment. But there are also some places where if they have no electricity, they can come just to stay warm, to get their phone charged, to get basic services that they also need,” Cilliers said.

The World Health Organization reports at least 715 hospitals and health care facilities have come under attack and been destroyed or damaged. Consequently, Cilliers said few facilities are available to treat people with war wounds, or those injured by mines or other unexploded ordnance, or suffering from illness and disease.