NEW YORK (CBSNewYork) -- As election day approaches, polls show Hillary Clinton's lead over Donald Trump growing.
Clinton knows how quickly those numbers can change, and she cautioned supporters not to get too comfortable, CBS2's Hazel Sanchez reported.
Meanwhile, Trump says people shouldn't believe everything they read. He said he's doing just fine.
With only 16 days to go, both candidates campaigned in key battleground states Sunday. Clinton was in North Carolina while Trump was in Florida, where CBS battleground polls have him trailing by three points.
The most recent ABC poll shows Clinton has a 12-point lead over Trump, with 50 percent support among likely voters nationwide.
Trump says the polls are wrong.
"It's rigged, it's broken, it's corrupt. They want me to take that back. Let me tell you folks. It's a rigged system, and we are going to drain the swamp of corruption in Washington, D.C." he said.
The Republican confidently told supporters that he's leading nationally.
His campaign manager was singing a slightly different tune, admitting Sunday morning that Trump is trailing. But she too was quick to play the blame game.
"We are behind. She has some advantages, like 66 million dollars in ad buys just in the month of September," Kelly Anne Conway said. "They system is rigged, and especially against the little guy."
CBS polls show 30 percent of likely voters in Florida say they believe voter fraud happens a lot. And if there was no fraud, 69 percent say they believe Trump would win.
Trump has said he won't question the election results, if he wins.
Clinton blasted Trump while making stops in Raleigh and Charlotte.
"He refused to say he would respect the results of this election, and that is a threat to this democracy," she said.
This weekend in Nevada, early voters waited in long lines to play their part in the democratic process, with Democrats far outnumbering Republicans on the first day of early voting, which could bode well for Clinton.
President Obama urged voters in Las Vegas not to be complacent.
"A guy who proves himself unfit for this office every single day every single way. And on the other side, you've got somebody who is as qualified as has ever run for the presidency: Hillary Rodham Clinton." Obama said.
Clinton and First Lady Michelle Obama will campaign together for the first time on Thursday in Winston-Salem, North Carolina.
Trump has publicly criticized the first lady's relationship with Clinton based on negative comments she made in 2007.
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