TENERIFE, Canary Islands, Spain (Reuters) -Thousands more people were evacuated from their homes on the Spanish island of Tenerife on Saturday as a wildfire raging in the north of the island remained out of control, but the flames have so far avoided major tourist areas.

The Canary Islands emergency services said more than 26,000 people had been evacuated by Saturday afternoon, according to provisional estimates, a sharp rise from 4,500 on Friday. Some 11 towns are now affected.

Fierce flames lit up the night sky overnight, and on Saturday helicopters were seen dropping water on areas close to homes where smoke was billowing into the air.

The blaze broke out on Wednesday in a mountainous national park around the Mount Teide volcano - Spain's highest peak - amid hot and dry weather.

More evacuations were ordered on Saturday morning due to worsening weather overnight, including a rise in temperatures and stronger winds, regional leader Fernando Clavijo told a press conference.

He said thick smoke was hampering efforts to extinguish the fire from the air.

Some 5,000 hectares (12,000 acres) have been burned so far with a perimeter of 50 km (30 miles).

The fire was at a scale that has never been seen before in the Canary Islands, Tenerife Council President Rosa Davila told reporters.

She said the priority was to "protect people's lives".

The blaze has not destroyed any homes so far, she added, citing the fire brigade.

In La Victoria, in the north-west of the island, some people who had been evacuated were receiving medical help.

"The night before we arrived, we had a pretty bad time. Everything was burning... the roofs were full (of ash)," Paulina Fernandez, 58, told Reuters.

A major concern for many evacuees was their animals. Some were forced to leave them at home, while Reuters footage showed others leading their horses to safety.

The island's popular tourist areas have so far been unaffected and its two airports have been operating normally.

Scorching heat and dry weather this summer have contributed to unusually severe wildfires in Europe, including in Spain's La Palma island in July, and Canada. Blazes on Hawaii's Maui island earlier this month killed more than 110 people and wrecked the historic resort city of Lahaina.

Scientists say climate change has led to more frequent and more powerful extreme weather events.

(Reporting by Nacho Doce and Jessica Jones, Writing by Jessica Jones; editing by Clelia Oziel)