A student at Eastern Middle School in Greenwich was approached by a stranger from behind Thursday morning on Lockwood Road, officials say.
The student told officials they were held for a few seconds but quickly released.
In a letter sent to parents, officials said that the student rushed to school and immediately reported the incident.
Officials said the student was unharmed but very sacred.
They recommend students walk to school with friends, remain aware of their surroundings and limit distractions such as cellphones.
Greenwich police say no one was injured, and the investigation remains active.