A school bus crash on the outskirts of Mexico City killed seven people, the Education Department said Saturday, correcting its original report of 12 deaths.

The bus toppled more than 25 feet off a bridge onto a highway linking the capital and the nearby city of Pachuca on Friday. Police said the driver, who has not been found, was likely speeding.

The Education Department on Saturday released the names of the seven teenage victims. Immediately after the accident, officials had said 12 people were killed.

Department spokeswoman Monica Garcia said officials had miscalculated the number of dead because injured bus passengers had been taken to a number of different hospitals and some were not immediately located.

A total of 28 students were injured in the accident, Garcia said. The bus driver is missing, she said.