ENLARGE Hillary Clinton, the presumptive Democratic presidential nominee, said she was saddened by the Republican National Convention. Photo: Getty Images .

By Harriet Torry Jul 24, 2016 7:00 pm ET 4 COMMENTS

Presumptive Democratic presidential nominee Democratic presidential nominee Hillary Clinton said she was saddened by chants at the Republican Convention calling for her incarceration for the use of a private email server while she was secretary of state.

“It felt very sad,” Mrs. Clinton said an interview on CBS “60 Minutes.”

“I don’t know what their convention was about, other than criticizing me. I seem to be the only unifying theme that they had,” she said, according to a transcript of the interview.

“There was no positive agenda. It was a very dark, divisive campaign,” Mrs. Clinton said.

Speeches at last week’s Cleveland convention prompted delegates to shout “Lock her up! Lock her up!” about Mrs. Clinton.

The Federal Bureau of Investigation found Hillary Clinton’s use of a private email server for official U.S. State Department business to be “extremely careless,” but recommended against charging her for mishandling classified information earlier this month.

Mrs. Clinton appeared alongside her newly selected running mate, Virginia Sen. Tim Kaine. Asked about whether they could achieve their agenda in a Republican-controlled Congress, Sen. Kaine expressed doubts Democrats could take back the House.

“I think the House is going to remain in Republican hands,” he told CBS. He expressed confidence Democrats could take control of the Senate.