A primary school teacher has been accused of teaching his male students to masturbate before urging them to take photos or film themselves in the act.

Joseph Kimerer Jr, 46, was arrested in Indiana on Friday over several masturbation incidents dating back to at least 2014.

Police said Kimerer had multiple victims ranging from 12 to 13 years of age while he was a fourth-grade teacher Amelia Earhart Elementary School.

Many of the alleged incidents took place during school hours, including during private baseball lessons, the Daily Mail reported.

The most recent incident occurred on February 26, according to police.

Kimerer is accused of asking the boys to masturbate in the bathroom and then later describe it to him.

He also allegedly asked the students about their penis sizes.

He allegedly asked the students to delete text message exchanges during which he asked about their penis sizes.

Kimerer, who was arrested at his home, has since been charged with 13 counts of sexual misbehaviourith minors, including attempted child exploitation and child solicitation.

Lafayette Schools Superintendent Les Huddle said police were immediately contacted and Kimerer was removed from the school after they learned of the allegations.

Huddle said the school is currently in the process of firing Kimerer following his arrest.

"We understand that these allegations will be very troubling to anyone who might have an association with Mr Kimerer," he said.

"The allegations are of the utmost gravity in that they implicate unprofessional conduct by a teacher towards a student.

"While this report is alarming, we want every parent and student to know that we will continue to provide a safe and nurturing environment for all students at Earhart Elementary and for all schools within the Lafayette School Corporation.'

Kimerer's bail was set at $500,000.