"A petrol bomb was hurled at the Government Girls School at Watergam in Rafiabad area of Baramulla district, causing some damage to the building," a police spokesman said.
He said there were no casualties reported in the incident that took place in the early hours of the day.
A polling station is located some distance away from where the petrol bomb landed, he said. Polling for Baramulla Lok Sabha constituency is scheduled to take place on Wednesday, May 7.
Security has been beefed up in the region ahead of the elections.