The hospital in the small Ukrainian town of Bakhmut was never intended to receive queues of ambulances bringing the wounded and traumatized from the front line of Europe's biggest battlefield.

Nor did the volunteer paramedics expect, four months ago, to be shuttling back and forth to the front line of a brutal tank battle, within earshot of rockets and shelling.

"I haven't seen so much human tragedy before. Absolutely unnecessary suffering," said Elena Bulakhtina, a Russian-born Canadian medic who joined the Pirogov First Volunteer Mobile Hospital, a group of civilian health care professionals dedicated to providing medical care on the front line.