The Astún resort in the Spanish Pyrenees, where the incident happened, was closed as rescue services attended the scene.

Images and video circulating on social media showed a number of people lying on the snow beneath the ski lift.

Spain’s Prime Minister Pedro Sánchez said he was “shocked” by the news of the incident.

Seventeen people needed medical attention, according to local media reports.

Ambulances and helicopters took some of the injured to nearby hospitals.

Dozens of people left hanging on the 15m (50ft) high chairlift have since been rescued, according to a regional official cited in local media.

A witness told the state broadcaster TVE that it looked like a cable had come off, the chairs had bounced and people were thrown from the lift.

An eyewitness who was on the lift told the BBC he saw a cable “lose tension” before the chairs on his side of the structure fell.

“It was very scary, but very fast,” Jamie Pelegri said – adding that ambulances and helicopters arrived at the scene within about 15 minutes.

Previously in a post on social media he had said it was the resort’s Canal Roya chairlift that had collapsed.

“Luckily we are fine but there are injured people, we have seen several stretchers coming down,” the Spotify commercial director said on X.

“We are talking about around 30 to 35 people injured, including serious, very serious and less serious injuries,” Miguel Ángel Clavero, the director of emergencies for the Aragon region, where the incident occurred, told TVE, according to AFP.

“Apparently, there was a failure in the return pulley of one of the chairlifts and this caused the cable to lose tension, causing some chairs to fall and others to remain hanging,” he said.

Images on social media purport to show one of the chairlift’s flywheels off its upright.

The cause of the incident is not yet known.

Regional president Jorge Azcón and Spain’s Minister of the Interior Roberto Bermúdez de Castro went to the ski resort to understand the extent of the accident.

Azcón wrote on X: “All the necessary services of the [government] are working to assist the affected and injured people.”

The Spanish prime minister, Pedro Sánchez, said he had spoken with Azcón “to offer him the “full support” of the government.

A telephone line has been set up for the families of those affected.

The Astún resort, which is popular with Spanish skiers, is located in the Aragon region of the Pyrenees mountains, near the border with France.