President Donald Trump said in an interview Tuesday night that he has had many difficult days as president, but that school shootings usually hit him the hardest.

“Well, we’ve had a lot,” the president said when asked about his most difficult day in office thus far by CSPAN. “You know, when you have a school shooting that’s tremendously — it angers me actually, it really angers me.” (RELATED: Trump Reacts To Texas School Shooting)

He continued, “It frustrates everybody. You say, ‘How could a thing like this happen?'”

WATCH:

.@SteveScully: “What was your most difficult day, thus far?” President Trump: “Well, we’ve had a lot…When you have a school shooting…That’s something that you just never can really get over.” Full interview at 9:55pm ET on C-SPAN https://t.co/nC1kPGJm5T pic.twitter.com/9y1vT2tKCT — CSPAN (@cspan) July 30, 2019

“That’s something that you just never can really get over,” he said.

Trump wondered out loud about potential solutions to school shootings, stating that the White House conducted a report on the issue. He added that the Marjory Stoneman Douglas school shooter in Parkland, Florida had many “red flags” on his record.

“People didn’t do what they should have done,” Trump asserted. “So those are events that are very tough to take when you’re the president of a country.”

17 people were killed in the Parkland shooting, which took place in February 2018. Subsequent reports revealed that people sent multiple warnings about the shooter to the FBI and local law enforcement that weren’t properly followed up on.