Portuguese Prime Minister Luis Montenegro has canceled his scheduled Thursday meeting. However, he is expected to participate virtually in a meeting of the so-called Goodwill Coalition in Paris, which will be chaired by French President Emmanuel Macron.

"It's a tragic day for our city... Lisbon is mourning, it's a tragic incident," Lisbon Mayor Carlos Moedas said on Wednesday evening.

Investigators say it is too early to determine the cause of the accident, but local media have quoted several people at the scene. One witness told Portuguese newspaper Observador that the vehicle was"uncontrollable, without brakes."

"We all ran away because we thought [the carriage] would hit something below. But it overturned on a curve and hit a building," said an eyewitness.

Police have not yet confirmed the identities of those killed in the accident. The Portuguese transport union Sitra reports that an employee of the Gloria funicular died in the accident.

At least 15 people were reported dead and 23 others injured when the popular Gloria funicular derailed in the Portuguese capital, Lisbon, on Wednesday evening.

The accident happened on Wednesday evening at around 6:05 p.m. Although the exact cause of the accident is not yet known, local newspaper Observador reported that the accident was caused by a broken cable on the funicular route, which caused the cable car to derail and crash into a nearby building.