The crash occurred near the Italian city of Verona on Friday night, killing 16 people, firefighters said Saturday.

Emergency workers said the vehicle struck a pylon shortly before midnight on the A4 highway and then burst into flames, the ANSA news agency reported.

Police commander Girolamo Lacquaniti said that no other vehicles were involved and that it was unclear why the bus crashed. He said that of the 39 people who survived, 26 were injured.

Bus was on a school trip

Most of the passengers on the bus were said to be Hungarian students, aged between 15 and 18.

Hungary's Foreign Minister Peter Szijjarto told reporters the teenagers were from a Budapest high school, and were returning from their annual ski camp in France along with teachers and parents.

"One passenger is currently in an induced coma and in life-threatening condition," Szijjarto said, adding that several other injured passengers were being treated in hospital for their injuries. Another 12 passengers were recovering at a hotel in Verona.

Uncertainty over passenger count

There have been conflicting reports about the number of passengers who were on the bus at the time of the crash.

Hungary's Foreign Ministry said it had information that there were 54 passengers, including adults accompanying the students as well as two drivers. But it believed there were additional people on board, for reasons which were unclear.

Szijjarto said there was uncertainty about exactly how many passengers were on the bus, but it was more than the director of the school had known about.

Hungarian Prime Minister Viktor Orban issued a statement, as authorities pledged support for the families of the victims.

"With my prayers, I am with the families and friends shocked by the tragedy," Orban said in a statement issued to Hungarian news agency MTI.

se/rc  (AFP, dpa, AP)