LISBON, Portugal — An electric streetcar that is one of Lisbon’s landmarks and a big draw for tourists derailed Wednesday, killing 15 people and injuring 18 others, emergency services said.

Five of the injured are in serious condition, and a child is among the injured, the National Institute for Medical Emergencies said in a statement. An unknown number of the injured are foreigners, it said.

Authorities called it an accident, the worst in the city’s recent history, and it cast a pall over Lisbon’s charm for the millions of foreign tourists who arrive every year.

The yellow-and-white streetcar, which goes up and down a steep downtown hill in tandem with one going the opposite way, was lying on its side on the narrow road that it travels along.

Its sides and top were partially crumpled, and it appeared to have crashed into a building where the road bends. Several dozen emergency workers were at the scene but most stood down after about two hours.

Eyewitnesses told local media that the streetcar careened down the hill, apparently out of control. Carris, the company that operates the streetcar, said scheduled maintenance had been carried out.

Portugal’s government announced that a day of national mourning would be observed on Thursday. “A tragic accident … caused the irreparable loss of human life, which left in mourning their families and dismayed the whole country,” it said in a statement.

Lisbon Mayor Carlos Moedas told reporters at the scene that the city was in mourning. “It’s a tragedy of the like we’ve never seen.”

President Marcelo Rebelo de Sousa offered his condolence to affected families.

European Commission President Ursula von der Leyen also sent her condolences. “It is with sadness that I learned of the derailment of the famous Elevador da Gloria,” she wrote in Portuguese on X.

The cause of the accident was not immediately known. It reportedly occurred at the start of the evening rush hour, around 6 p.m. Emergency officials said all victims were pulled out of the wreckage in just over two hours.

An investigation into the causes will begin once the rescue operation is over, the Portuguese government said.

The streetcar, known as Gloria, can carry more than 40 people, seated and standing. It is also commonly used by Lisbon residents.

The streetcar, technically called a funicular, is known as Elevador da Gloria. Two streetcars run parallel to each other as they shuttle up and down the hill on a curved, traffic-free road for a few hundred meters (yards). They are harnessed by steel cables.

It is classified as a national monument.

Lisbon hosted around 8.5 million tourists last year, and the streetcar is a popular attraction. Long lines of tourists typically form for the brief ride on it.