A fierce storm from the Atlantic Ocean hit southwestern France and northern Spain over the weekend, leaving at least 15 people dead and one million homes without power.

With torrential rains and winds approaching 175 kilometres an hour, the storm was described by weather forecasters as the region's worst in a decade.

Four children died and 16 others were injured when part of a sports centre collapsed in high winds in the northeastern Spanish city of Barcelona, officials and witnesses said.

At least 11 adults died in separate incidents in France and Spain, including two crushed by falling trees in Catalonia.

In Bordeaux's Gironde region, rescuers evacuated 19 residents of a retirement home after its rooftop was swept away.

The storm also forced roads, airports and railways to close on Saturday in France.

As the storm moved to the central Mediterranean Sea on Sunday, the French and Spanish governments called in their armies to help civilians. French Interior Minister Michèle Alliot-Marie announced that an additional 715 civil security agents would be deployed in the country's affected regions to help repair power outages, telephone lines and railway networks.

France also dispatched 5,000 firefighters from across the country to the devastated areas.

The Spanish army was supporting emergency services fighting a forest fire in Alicante, north of the resort of Benidorm, which started when gales felled an electricity pylon, the BBC reported.

In December 1999, 88 people died and nearly four million homes were without electricity during a storm that hit northern France. That one prompted France to create a weather-alert warning system, which it credited this weekend for avoiding more casualties in the latest storm.

With files from the Associated Press