A police constable was injured while two government vehicles were damaged in stone pelting by angry protesters, police said.
The accused, identified as Vijay Kumar, who used to teach music in A-block Sarvodaya Vidyalaya, Jahangirpuri, was arrested in the afternoon after the victims' parents and locals staged an angry protest alleging that he had molested the girls.
"A case under section 354 IPC (molestation) and POCSO (Protection of Children from Sexual Offences) has been registered against the accused at Mahindra Park police station and investigations are on," said a senior police official.
"The parents claim that instead of cooperating with them or taking action, the school Principal threatened against going to police and asked them to leave the premises," the official said.