A heckler interrupted President Obama's speech at Notre Dame this afternoon.

A voice yelled out early on in Obama's address, forcing him to stop and wait for the protester to be removed. Notre Dame grads began a chant to drown out the heckler before Obama asked everyone to calm down.

It was unclear whether the heckler was upset with Obama's abortion stance, which has become a flashpoint leading up to his commencement address at the Catholic University.