"There were 45 children and teachers in the bus when the speeding truck collided with it on the highway this afternoon," a senior police official said.
The bus was plying students of a private school located near Vasco, around 40 kms from here.
The seven seriously injured children were shifted to district hospital nearby. The others were treated at a Primary Health Centre as they sustained minor injuries, he said.
The truck driver fled from the spot after the accident, police said, adding a search was on to nab him.