The incident occurred at around 7.20am on Rambla Ferran when the vehicle suddenly mounted the pavement.

Footage from a nearby security camera showed the bus travelling normally down Rambla Ferran towards the Pont Vell before it suddenly veered across the road before mounting the pedestrianised zone and colliding with the provincial council building.

Catalonia’s Medical Emergency System (SEM) confirmed that alongside the four critical patients, nine people are in a serious condition, with the remaining passengers sustaining minor injuries.

Among those seriously injured is a driving instructor who was accompanying the driver; officials confirmed the instructor suffered a severed limb in the impact.

Local authorities stated that the vast majority of the passengers were seasonal agricultural workers commuting to the southern Segrià region for the fruit harvest.

The scale of the crash triggered a massive rescue operation, with the SEM deploying 11 road units, a medical helicopter and trauma psychologists, alongside 14 crews from the regional fire service.

The regional health department confirmed that 21 casualties were rushed to the Arnau de Vilanova Hospital, where five underwent emergency surgery and another five were admitted to intensive care.

A further 21 victims were treated for minor contusions at the CUAP Lleida urgent care centre, 20 of whom have already been discharged.

The regional police, the Mossos d'Esquadra, have launched an investigation into the cause of the crash and are examining whether the vehicle suffered a mechanical failure. Investigators will take statements from passengers and eyewitnesses.

The mayor of Lleida, Fèlix Larrosa, confirmed that the driver had only recently joined the bus company. He added that it was "a matter of centimetres" that pedestrians on the busy avenue were not hit, confirming that no one on the pavement was caught up in the crash.

The President of Catalonia, Salvador Illa, expressed his solidarity with the victims and their families, offered his full support to municipal leaders and thanked the emergency services for their rapid response.