'I'm starting to agree with you': Trump eggs on 'lock her up' chant at rambunctious rally

Donald Trump gave some fire to a crowd of supporters chanting during a campaign rally in Colorado Springs on Friday.

While lambasting Hillary Clinton over the FBI's investigation into her use of a private email server at the State Department, the crowd reprised the anti-Clinton "lock her up" chant that gained traction during last week's Republican National Convention.

That chant was repeated vigorously throughout the convention, but Trump himself had demurred when the chant broke out, typically saying instead that he would beat Clinton on Election Day.

But the real-estate mogul signaled his approval during the Friday rally. Speaking over the chants, Trump said, "I've been saying, let's just beat her on November 8.

But you know what?" he added. "I'm starting to agree with you."

"Every time I mention her, everyone screams 'lock her up' ... and you know what I do, I've been nice. But after watching that performance [Thursday] night - such lies - I don't have to be so nice anymore. I'm taking the gloves off."

The room erupted in cheers.

Clinton formally accepted the Democratic nomination for president on Thursday night. In her primetime speech, Clinton took several jabs at Trump, including one line that attempted to sum up the Republican presidential candidate in a nutshell.

Said Clinton: "A man you can bait with a tweet is not a man you can trust with nuclear weapons."

Trump spent much of the Colorado rally attacking Clinton, but he also devoted time toward litigating past controversies along the campaign trail, such as his alleged mocking of a disabled reporter and his claim that Arabs in New Jersey cheered the attacks of September 11, 2001.

Watch the full rally below: