At least 53 people have been killed after a devastating storm lashed France and four other countries in western Europe over the weekend.

The storm, called Xynthia, whipped up powerful winds and torrential rains that blew off roofs, uprooted trees and washed away roads across the region.

It also took down power lines, leaving nearly 900,000 people in France without electricity.

Francois Fillon, France's prime minister, said France would formally declare the storm a natural disaster, a move that would free up funds to help people rebuild.

Many drowned in Sunday's disaster, while others were struck by collapsing debris as parts of buildings or trees and branches were ripped off by fierce winds.

France was the worst hit country, with officials putting the death toll at 45 people.

Strong gusts and high tides destroyed Atlantic coast sea walls, killing 25 people in the town of l'Aguillon sur Mer alone, city officials told French television.

France devastated

The French regions of Vendee and Charente Maritime bore the brunt of the storm and were placed on flood alert along with parts of Brittany.

Helicopters lifted people to safety throughout the day.

Xynthia also caused death and damage Spain, Germany, Portugal and Belgium [EPA]

The government announced an immediate relief fund of 1 million euros ($1.36m) and tax relief for victims.

France also plans to ask the European Union to release funds from its regional budget to help pay for recovery operations.

Elsewhere, the storm caused the deaths of three people in Spain, another three in Germany and one each in Portugal and Belgium.

Nearly 60 others were injured and more than a dozen are missing.

Although Britain was not hit, London's Thames Barrier, the capital's flood defence, was closed on Sunday morning as a precaution.