MEXICO CITY (Reuters) - At least 19 people were killed in central Mexico on Monday when a bus crashed into a truck and burst into flames, authorities and news media said.

The bus, traveling from Mexico City to the northern city of Zacatecas, collided with the truck before dawn in Queretaro state, the Excelsior newspaper said on its website. At least 16 passengers and three other people died, it said.

Photographs of the charred bus showed only its chassis and engine remaining.

The Queretaro public security ministry said there was an accident but could not confirm the number of fatalities. News media initially reported at least 21 deaths but then revised the number downward.

(Reporting by Patrick Rucker; Editing by John O'Callaghan)