The event came to an event after Bush had taken a question about racial disparities in the criminal justice system. Bush said that "these problems have gotten worse in the last few years" and that communities "no longer trust the basic institutions in our society that they need to trust," according to CNN.
As Bush exited, some chanted "Black lives matter" while others chanted "White lives matter" or "all lives matter."
Two women -- a protester and a Bush supporter -- stood a few feet from the candidate with their middle fingers extended in each other's faces, according to the Los Angeles Times.
The event was held at the Pearson Community Center in North Las Vegas, a predominantly Black community. The community center is run by the Urban League; Bush addressed the group's national convention in Florida two weeks ago.
Bush spokeswoman Allie Brandenburger said that Bush met with Black Lives Matters advocates "ahead of his event in Las Vegas on issues including criminal justice reform. As Governor Bush laid out in is speech to the Urban League, he is committed to campaigning across the nation as he seeks the presidency, talking to everyone and every community about his vision for restoring opportunity for all Americans."
"Gov. Bush listened to the group and they discussed barriers to upward mobility in this country, and ways to overcome them as a community by starting to get a few things right in government," she added.
Representatives of the group -- who had alerted reporters earlier Wednesday about their plans -- didn't immediately respond to requests for comment.
"Black Lives Matter" activists have disrupted several political events in recent weeks, including rallies held by Democratic presidential candidate Sen. Bernie Sanders. Democratic frontrunner Hillary Rodham Clinton met with group activists on Tuesday in New Hampshire after they arrived too late to get seats in the main room. They had also previously alerted reporters there of their plans to show up and ask questions about mass incarceration.