Thousands evacuated in raging wildfire on Spain's Tenerife island

"The fire is still advancing ... but the priority is to defend the population centres tonight," the region's leader, Fernando Clavijo, told a press conference near midnight.

Earlier he said the wildfire is the most complex the Canary Islands has faced in the last 40 years.

The emergency services are expecting temperatures to rise on the island over the weekend and a change in winds from the early hours of Saturday morning could push the fire westwards from northeastern Tenerife.

"The evolution of the fire is slower now," the head of the island's emergency service, Pedro Martinez, told reporters. Around 200 firefighters will continue to work through the night.

Early in the day, while waterbombing aircraft managed to stabilise the blaze south of the Mount Teide volcano - Spain's highest peak - the flames advanced "out of control" on the northern flank across dry woodland towards a valley where several camping sites are located, blanketing much of the island with smoke and ash.

"When you go outside you start suffocating. It's as if you have something stuck in your throat," said Alba Gil, 37, resident of the village of La Esperanza where authorities ordered people to stay home due to the heavy smoke. She and her family stayed up until 4 a.m. worried about the flames higher up the mountain.

The fire, which broke out on Wednesday, has burned through at least 3,273 hectares (8,088 acres) of land.

Scorching heat and dry weather this summer have contributed to unusually severe wildfires in Europe and western Canada. Hawaii's Maui was also hit by wildfires which have killed at least 106 people, forced tens of thousands to evacuate and devastated the historic resort city of Lahaina.

Scientists say climate change, driven by fossil fuel use, has led to more frequent and more powerful extreme weather events.

Last week's heatwave in the Canary Islands left many areas bone dry, heightening the risk of wildfires.

Authorities warned the spreading blaze could lead to further evacuations and confinement, advising people to stay tuned to public service alerts. So far, 3,820 people were ordered to stay home until tomorrow, said civil protection chief Montse Roman.

A prison and a migrant reception centre were in the areas under confinement.

Authorities deployed 17 aircraft and a combined 350 firefighters and military personnel. On Friday, 16 aircraft will resume duties as a result of a helicopter malfunction, Roman added.

"We are watching the big mountain and the blaze, we saw this firewall and we'll see if they can control it, the situation seems pretty bad," said resident Celestino Suarez, 53.

All access to the mountains on the island, including tourist-favourite Mount Teide and the Teide Astrophysics Institute, has been closed off to prevent any incidents.