Obama: I was surprised I teared up

President Obama said he was surprised that he teared up earlier this week when recalling the 2012 Sandy Hook Elementary School shooting that left 20 children dead.

During Obama's town hall debate on guns, CNN's Anderson Cooper played footage of Obama becoming visibly emotional during a Tuesday press conference. Cooper said many were surprised by the moment.

"I was too, actually," Obama responded soberly, discussing the aftermath of the shooting in Newtown, Conn. "I visited Newtown two days after what happened, so it was still very raw."

"It's the only time I've ever seen Secret Service cry on duty," Obama added, reiterating that it was one of the worst days of his presidency. "It continues to haunt me."

Obama's emotion during his Tuesday press conference become the subject of debate after a Fox News contributor suggested he faked the tears.

George Zimmerman, who gained national attention in the shooting of Trayvon Martin, also blasted Obama's "crocodile tears."

But GOP presidential front-runner Donald TrumpDonald TrumpObama reads mean tweet from Trump on ‘Kimmel’ 5 takeaways from the Pa. Senate debate Report: Clinton ordered operative to troll Trump with duck MORE said he thought they were sincere.

Speaking of police officers slain in the line of duty, Obama said Thursday, "Tears are appropriate for them as well, and I visit with those families as well — victims of terrorism, soldiers coming home."

"There's a lot of heartache out there, and I don't suggest that this is only the kind of heartache we should be working on," Obama said of gun violence.