Shrikant Sharma, 38, the principal of S.S. Convent School in Majhola town was Thursday arrested for molesting the two girls of class 1 and 2.
Sharma Wednesday forced the two girl students to perform obscene acts with him in a vacant class room of the school.
"The girls' parents approached us Thursday, following which we conducted a preliminary inquiry. Prima facie, the charges against the principal were found true, so we arrested him," Police Inspector Sanjay Singh told reporters in Moradabad, some 350 km from Lucknow.
"A detailed probe is underway to ascertain involvement of other school staff in the crime and to know whether other girls in the school were ever molested by the principal," he added.