US President Donald Trump has stirred debate by asking why the American Civil War happened, and pondering whether it could have been "worked out".
In a radio interview, he suggested the conflict might have been avoided if President Andrew Jackson had still been in office.
The 1861-65 Civil War between the northern and southern states was principally caused by slavery.
Mr Jackson, who was president from 1829-37, was a slave-owner himself.
"I mean, had Andrew Jackson been a little later you wouldn't have had the Civil War," Mr Trump said in an interview with a Washington Examiner reporter, broadcast on Sirius XM.
"He was a very tough person, but he had a big heart.
"And he was really angry that he saw what was happening with regard to the Civil War. He said, 'there's no reason for this.'"
Critics suggested the president appeared to believe Jackson was still around during the secessionist conflict, although he died 16 years beforehand.
Mr Trump continued: "People don't realise, you know, the Civil War, if you think about it, why?
"People don't ask that question, but why was there the Civil War?
"Why could that one not have been worked out?"
Mr Trump has frequently likened his campaign to that of the populist, seventh US president. In March he even visited Jackson's tomb in Nashville, Tennessee.
In the interview, Mr Trump noted that Jackson "had a very, very mean and nasty campaign" and "unfortunately it continues".
The president's remarks were labelled "totally bizarre" by the Washington Post.
But the journalist who conducted the interview played down the criticism of Mr Trump.
"Context is everything," tweeted Salena Zito.