According to the police, the accident took place as the city was enveloped in a thick blanket of fog. The bus was carrying 30 students.
The victims, students of Guru Arjun Dev Public School, a private school located near Saha are between the age group of 5-8 years. They have been rushed to the Civil Hospital in Ambala Cantt.
While 20 students have been injured, 8 are reportedly serious.
Rescue operations have started and officials of the Ambala district administration rushed to spot after being alerted about the incident.
Those killed in accident have been identified as Rahul, Divya, Raveesh, Rishab, Harish, Anu and Pulkit.