Democratic presidential hopeful Bernie Sanders says that he’s getting a boost in the polls because “people are saying enough is enough” when it comes to America’s political and economic systems.

“A lot of these people are young people, working class people, who understand that both the economics of America today and the politics of America today are rigged in favor of the wealthy and the powerful,” Sanders told NBC’s Andrea Mitchell in the first interview since a New Hampshire poll showed him with an apparent lead over Hillary Clinton in that key primary state.

Sanders said that his momentum is “not just in polls,” but also in his burgeoning crowd sizes. Over 20,000 people attended each of his rallies in Los Angeles and Portland in recent days.

“People are saying ‘enough is enough,’ and I think we’re seeing a lot of support for our campaign as a result,” he said.

Sanders declined to criticize Clinton over the swirling controversy involving her use of a private server for email correspondence during her tenure as Secretary of State. Clinton announced yesterday that she will turn that server over to investigators.

“I honestly believe the American people are tired of old-fashioned politics where you’re supposed to be beating up all your opponents,” he said. “We’re trying to run a campaign which is not negative, but which talks to the needs of middle class and working families, which creates an economy that works for everybody and not a handful of billionaires.”