Pete Buttigieg confronts Pence about religion ahead of 2020 bid

Gay rights and religion are at the heart of a simmering feud between Vice President Mike Pence and potential Democratic presidential candidate Pete Buttigieg. The 37-year-old mayor of South Bend, Indiana, who is openly gay, criticized Pence Friday for his opposition to gay marriage and gay rights, which Pence claims is informed by his Christian faith.

"I don't have a problem with religion, I'm religious too. I have a problem with religion being used as a justification to harm people," he said on "Ellen."

"I hope that Pete will offer more to the American people than attacks on my Christian faith or attacks on the president as he seeks the highest office in the land," Pence said.

The vice president said he doesn't believe in discriminating against anyone.

"I think Pete's quarrel is with the First Amendment. All of us in this country have the right to our religious beliefs," Pence said.

Pete Buttigieg criticizes Mike Pence for his stance on gay marriage, cites his own religious beliefs

Last month, Buttigieg began raising questions about the vice president, whom he worked with when Pence was governor of Indiana.

"How could he allow himself to become the cheerleader of the porn star presidency? Is is that he -- is that he stopped believing in scripture when he started believing in Donald Trump," Buttigieg said.

In 2015, when both men were serving in Indiana, Pence signed a law that critics say unfairly targeted members of the LGBTQ community. At the time, Buttigieg was just months from coming out as gay. The law was eventually rolled back amid a national outcry.

Today, Buttigieg is surging in the polls, placing third in both Iowa and New Hampshire. He's an Afghanistan war veteran and a Harvard grad, with a famously tricky last name.

After more than three months of officially exploring a run, Buttigieg formally filed paperwork to run for president. He's expected to officially kick off his campaign Sunday in South Bend.