Bavarian police say 30 others were injured, some seriously, and were brought to hospitals for treatment. The others, they said in a statement Monday, "are believed to have died on the burning bus."
Police spokeswoman Irene Brandenstein says the bus was carrying a German senior citizens' tour group.
Earlier, officers said they fear a number of people may have died when the bus went up in flames.
"We're afraid that people may have died in the accident," police spokeswoman Irene Brandenstein told The Associated Press.
She said several people were severely injured in the crash near Muenchberg in Bavaria.
PHOTOS: Crashed bus erupts in flames in Germany
Local Oberfranken police tweeted that the travel group came from Saxony in eastern Germany and that a phone number had been activated to provide family members with information.
Two drivers and 46 people and were on the bus, Brandenstein said.
German news channel n-tv showed images of the bus which was burned down to a black, smoking skeleton.
Several helicopters and ambulances were on the scene to rescue the injured and the A9 highway was closed in both directions because of the accident.
Brandenstein said the bus crashed into the truck at the end of a traffic jam. She had no information immediately about what happened to the truck driver. She said she had no information about who was on the bus.
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