Italian authorities are investigating whether the driver of a bus that plummeted 50 feet (15 metres) from an elevated road in Venice, killing 21 people and injuring at least 15, had fallen ill before the crash. Those who died in the Tuesday night crash included the Italian driver, at least five Ukrainians and one German citizen, according to the Venice prefecture. Regional governor Luca Zaia said that that the dynamic of the accident remained hard to decipher. "Everything makes one think of an illness," Mr Zaia said. "The driver was an expert, a good person, very well referenced." At least two of the dead were children, Venice prefect Michele Di Bari said, adding that many of the people involved in the accident were "young." Nine people were in critical condition, hospital officials said later on Wednesday, including a three-year-old girl from Ukraine. The Venice prosecutor Bruno Cherchi said he was proceeding with a multiple road homicide investigation into the bus crash. Speaking at a press conference, Mr Cherchi said an autopsy on the driver’s body would be important for the case. Firefighters worked until dawn to clear the wreckage. Later in the morning on Wednesday, traffic was slowly passing the spot where the bus burst through a guardrail and a rusted fence. The bus was carrying foreign tourists from Venice's Piazzale Roma to the Hu campground on Tuesday evening when it fell from an elevated street next to railway tracks in the borough of Mestre, catching fire. Tourists frequently stay in boroughs across the lagoon from the canals of Venice's famous historic center to find cheaper accommodations. The injured included French, Spanish, Austrian and Croatian nationals, local officials said. The Spanish Foreign Ministry said on Wednesday that two people from Spain were injured in the accident, and both were in hospital and in good condition. The French Foreign Ministry confirmed on Wednesday that there was a French national among the injured. Hospital psychologists were working to help the victims deal with the trauma. Rescuers noted that the fact that the bus was electric contributed to the massive fire and made rescue operations more difficult. Godstime Erheneden was in his apartment near the site when he heard a crash. He rushed outside and was among the first to enter the bus. "When we went in, we saw the driver right away. He was dead. I carried a woman out on my shoulders, then a man," Mr Erheneden told the local newspaper il Gazzettino. "The woman was screaming, 'my daughter, my daughter,' and I went back in. I saw this girl who must have been two years old. I have a son who is a year and 10 months old, and they are the same size. I felt like I was holding my son in my arms. It was terrible. I don't know if she survived. I thought she was alive but when the rescuers arrived, they took her away immediately," Mr Erheneden said. Venice Mayor Luigi Brugnaro wrote on X, formerly known as Twitter, that the scene was "apocalyptic" and declared a state of mourning. In 2017, 16 people on a bus carrying Hungarian students died in an accident near the northern city of Verona. And in 2013, 40 people were killed in one of Italy's worst vehicle accidents when a bus plunged off a viaduct close to the southern city of Avellino. Associated Press Read More Firefighters work until dawn to remove wreckage of bus carrying tourists in Venice; 21 dead At least five foreign nationals among 21 killed in Venice bus crash – latest At least 21 dead after passenger bus plunges off overpass near Venice A bus crash near Italian city of Venice kills at least 21 people, including Ukrainian tourists 'PAW Patrol' shows bark at box office while 'The Creator' and 'Dumb Money' disappoint At the New York Film Festival, a sluggish fall movie season seeks a higher gear