MASSIVE flooding in France and Italy has killed at least four people and left dozens trapped or missing, authorities revealed today.

A storm that moved across south-eastern France and into north-western Italy over the weekend caused major flooding on both sides of the border, destroying bridges, blocking roads and isolating communities.

In Italy, a firefighter was confirmed killed during a rescue operation after a search team found a body that had been swept away by floodwater late on Friday.

Italian firefighters used a helicopter to ferry 17 people, including a woman and her two grandchildren, to safety from the French town of Vievola. 

A bulldozer fetched another eight who had managed to climb the Col de Tende, a high mountain pass linking France and Italy, to reach a tunnel.

Fifteen more people were sheltering in Vievola railway station after an operation to rescue them was put off until daylight.

Across the border in France, almost a year’s average rainfall fell in less than 12 hours in the mountainous area around the coastal city of Nice. 

French authorities deployed about 1,000 firefighters, four military helicopters and troops to search for at least eight people who were missing, including two firefighters whose vehicle was swept away by water when a road collapsed.

Nice Mayor Christian Estrosi said that more than 100 homes had been were destroyed or severely damaged in the area.

French Prime Minister Jean Castex, who flew over the flood zone in a helicopter, said: “I cannot hide our grave concern over the final toll.”

Many worried families had not heard from their relatives due to mobile phone services being cut off in the area.

“As I speak, priority goes to searching for victims, providing supplies and accommodation for the people affected and restoring communications,” Mr Castex said.