Portugal declared a day of national mourning on Thursday after a funicular train derailed in Lisbon, killing at least 17 people in one of the capital's most popular tourist spots.

The accident on Wednesday saw the yellow Gloria funicular veer off a steep stretch of tracks near Liberty Avenue and crash into a building.

Rescuers said a further 21 people were injured. The victims, including some foreigners, have all been recovered from the wreckage, according to the emergency services.

The Portuguese government said the country would observe a day of mourning on Thursday to commemorate the victims, whose identities were not immediately available.

Footage showed police and rescue personnel working into the night around the mangled funicular lying on its side against a wall of the street.

Lisbon 'in shock' after deadly funicular crash

A woman interviewed by the SIC television channel said the train, which can hold about 40 people, struck the building"with brutal force and collapsed like a cardboard box".

Lisbon Mayor Carlos Moedas called the incident"a tragedy that our city has never seen".

A statement by the office of Prime Minister Luis Montenegro said it had"brought grief to... families and dismay to the country", and European Union chief Ursula von der Leyen offered condolences to the victims' families.

Lisbon prosecutors said they were opening an investigation into the accident's circumstances.

The city's public transport operator said it had complied with"all maintenance protocols".

"Everything was scrupulously respected," Pedro Bogas, the head of Lisbon Carris, said at the site of the accident, adding that maintenance of the funiculars has been done by a contractor for the past 14 years.

General maintenance is carried out every four years and was last conducted in 2022, Carris said. Intermediate maintenance takes place every two years and was completed in 2024.

Antonio Javier, a 44-year-old Spanish tourist, told AFP his family were"a little relieved" to have skipped taking the funicular because the queue was too long.

Tourists and residents alike use Lisbon's funiculars to travel up and down the capital's steep hills and the boxy yellow train is a common image on gift shop souvenirs.

The Gloria first entered into service in 1885 and was hooked up to electricity in 1915, according to the website of Portugal's national monuments.