A Paramus third-grade student was seriously injured by a rock thrown at a school bus on its way back from a field trip earlier this week, officials said.

New Jersey State Police are seeking help in finding who threw a rock at a bus on the New Jersey Turnpike near Exit 70A/B around 2 p.m. Wednesday that was transporting children to the Yeshivat Noam school.

The rock struck an 8-year-old girl, who sustained a skull fracture and will need surgery, school officials said in an email to parents.

“Our focus remains on supporting the injured student and her family, as well as ensuring the emotional health of our entire student body," the school said in a statement. "We are working closely with law enforcement to ensure a thorough investigation.”

Police say the bus was traveling northbound on the turnpike when the rock shattered a side window and struck the girl.

Teaneck officials are offering a $5,000 reward for information leading to an arrest.

Witnesses or anyone who may have information about the incident are asked to call the Troop D Newark Station Detective Bureau at 732-441-4500, ext. 1401.