VENICE: Flags flew at half-mast over Venice on Wednesday after 21 people including a toddler were killed when a bus careered off an overpass and caught fire.

`The bus flipped upside down. The impact was terrible because it fell from over 32 feet` landing next to railway tracks below, said Mauro Luongo, Venice`s fire brigade commander.

The deadarethoughtto be mostly tourists returned from Venice`s historic centre to a camping site on Tuesday evening. Fifteen others were injured in what Venice Mayor Luigi Brugnaro described as `an apocalyptic scene`.

Firefighters said the bus was electric, despite the Italian interior minister earlier saying it ran on methane. They spent hours extracting bodies from the charred remains of the bus, which was finally removed from the site in the early hours of Wednesday.

`Among the difficultieswas the fact that the bus was electric so it had batteries. Unfortunately, they caught fire on impact,` said Luongo.

`That`s why operations took a little longer to remove the vehicle.` Luca Zaia, the governor of the Venice region, confirmed the official death toll was 21, `including a one-yearold child and a teenager`.

Five Ukrainians were among the dead identified so far, alongside a German, a Croatian, a Frenchman and the Italian driver, he said.

Five of the 15 injured are in a `very serious condition`, and some were still being identified, he said.

Firefighters said the bus caught fire after careering off an overpass straddling a railway line and linking the mainland Mestre and Marghera districts of Venice in northern Italy.

Zaia said that flags on official buildings in the region would be put at half-mast because of this `tragedy of enormous proportions`.-AFP