Kateryna Krupich and her two children were left stranded in an attic as floodwaters from the destroyed dam rose beneath them
Kateryna Krupich and her two children were left stranded in an attic as floodwaters from the destroyed dam rose beneath them AFP

Kateryna Krupich and her two children climbed into the attic of a three-storey house, watching with horror as waters from a destroyed dam in southern Ukraine swallowed up the floors below them.

The family was stranded under the rooftop of a neighbour's house on a heavily-flooded island near the Russian-occupied town of Oleshky without food and drinking water for almost 24 hours.

With most of the house engulfed by floodwaters, they were running out of hope when they heard the buzz of a drone overhead.

Recounting her ordeal through her tears, 40-year-old Krupich told AFP she realised it was a Ukrainian drone.

The desperate mother leant out of the window and raised both hands in a prayer gesture.

"I show them that there's three of us here, and we have nothing to eat or drink. Please help," she said.

The drone flew back and forth several times, delivering food supplies -- and a message taped to a plastic bottle.

Krupich broke down in tears when she read the note.

"I've decided to keep it to remember what we have been through," she said in the city of Kherson after she, her 12-year-old son and four-year-old daughter were evacuated.

"This is what we needed at the time."

The family was rescued by a Ukrainian team on Wednesday evening.

The video of Krupich pleading for help -- made by the Ukrainian border guard service -- went viral on social media in the war-torn country.

Krupich and her children lived under Russian occupation for more than a year. There were just a dozen people left on the tiny island of Chaika.

"We lived all these months cut off from everyone," she said.

"We fished and ate supplies that the neighbours allowed us to take from their homes."

When the Russian-controlled Kakhovka dam was breached on Tuesday, the island started going under water.

While Ukrainian authorities quickly launched a rescue operation, many living on Russian-controlled territory say they have been left to their own devices.

"The day the dam of the Kakhovka Hydroelectric Station was blown up, I saw the Russians flee," said Krupich.

Ukraine and Russia have accused each other of causing the breach.

Krupich said she was frightened to see the water levels rise so quickly.

"Ten centimetres every half an hour. Then another 10 centimetres, then another 10 centimetres," she said.

The water was up to their ankles, then their knees. The houses on the island were slowly disappearing, and the floodwaters carried waste and debris.

It was dangerous to remain in their one-storey house so they moved into a neighbouring three-storey building and hid in the attic.

"It was scary to watch windows go underwater," said Krupich, referring to her own house.

"Then the water reached the roof, and then the roofing started to disappear."

Her family was rescued by a 31-year-old member of Ukraine's border guard who spotted them with the help of his drone.

The serviceman, who identified himself by his call sign Santa, operates a commercial drone used for monitoring purposes during Ukraine's war effort.

Using his aerial vehicle to drop food supplies into a small rooftop window was a first for Santa, he said.

"People call it a wedding drone," he said, adding that in peacetime such drones are usually used to capture expansive footage from overhead.

"In wartime, we have learnt to use it a little bit differently. Replacing a grenade with a bottle of water is not a problem, they weigh the same," said Santa, his face covered with a mask.

Santa said he needed to remain anonymous due to his line of work but revealed he has a beard -- hence his call sign.

Krupich and her kids see camouflage-clad Santa as their saviour.

"He's my guardian angel," she said.

But Santa says he was just doing his job.

"When you see a mother with two minor children, you instantly make a decision," Santa said, smiling behind his mask.

"You direct all your efforts towards helping this family."