A bus carrying foreign tourists including Ukrainians crashed near the Italian city of Venice when it fell from an elevated street Tuesday, killing at least 21 people and injuring 18 others, authorities said. 

Four of the injured were in serious condition following the accident in the Mestre borough, on the mainland opposite the historic old city of Venice, said Renato Boraso, a Venice city official. Two of the dead were children, Venice prefect Michele Di Bari said. 

Boraso confirmed that some of the victims are Ukrainians, and said the bus was bringing tourists to a camping site. 

Venice Mayor Luigi Brugnaro wrote on X, formerly Twitter, that the scene of the crash was "apocalyptic" and that he had already declared the "city's mourning" for the "numerous victims" who were on the bus. 

According to local media, the bus fell a few meters before crashing close to Mestre's railway tracks, where it caught fire. Emergency crews were on the scene. 

Premier Giorgia Meloni expressed her "deepest sorrow" after the crash. 

-GIADA ZAMPANO, AP