(CNN) At least 30 Indian girls are recovering at a government-run boarding school in the country's eastern Bihar state after they were beaten up by a group of teenage boys -- and their parents -- on Sunday.

The girls, between the ages of 11 to 16, were playing inside the school compound in Bihar's Supaul district when the group of boys showed up and wrote "lewd messages" on the school's wall.

The girls first addressed the boys' messages in a "heated argument" that eventually turned physical, according to Mrityunjay Kumar Chaudhary, superintendent of police. A group of more than 60 girls initially "overpowered" the boys, so they ran away, only to return with adult reinforcements, he said.

"(They) came back with their parents. The boys with their parents barged into the school, beat up the girls," Chaudhary said.

Dr. Prakash Kumar of Supaul's Anumandaliya Hospital said 38 girls were brought for treatment and that none of the girls suffered serious injuries.

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