MESTRE -- Dozens of Ukrainian, French, Croatian and German tourists were killed or injured Tuesday when a private coach ferrying them from Venice to a nearby campsite plunged off a bridge onto a railway line and caught fire after striking overhead railway electricity cables, firefighters said.

 At least 21 people were killed including the Italian bus driver and two children and at least 12 other campers were seriously injured in the accident, the latest in a rash of disasters that has made road travel in Italy the most hazardous in western Europe, firemen said.

 Firefighters and rescue workers toiled under floodlights to pull survivors from the tangled wreckage. The cause of the accident was not immediately known but investigators speculated the driver, 40, may have had a heart attack, the bus was powered by inflammable methane gas and the fuel tank exploded leaving the 40 people aboard little chance to escape the flames.

 First rescue efforts were by two Gambian migrant workers who pulled some passengers from the blaze, earning praise from rescue workers. At least 50 ambulances were ferrying bodies and survivors away from the scene while local people congregated ghoulishly to film the scene on their mobile phones.

 jp