By Julia Manchester CNN

(CNN) -- Donald Trump told a crowd of supporters in Florida Monday that he is in the lead in the race for the White House, despite being behind in the majority of national polls.

"Some great polls have just come out. I believe we're actually winning," Trump said, slamming the mainstream media.

The GOP presidential candidate went on to cite two polls, which he said show him leading Clinton.

"The Investors (Business) Daily poll, which was the single most accurate poll for the last three cycles. The last three presidential races. We're up. We just went up. We were down three. We were down five. We're now two up in Rasmussen. Just came out this morning. We're up in another couple of polls," Trump said.

Neither the IBD/TIPP nor the Rasmussen polls meet CNN's polling standards, for different reasons. IBD/TIPP poll does not disclose critical pieces of its methodology and Rasmussen uses a blend of online and telephone polling without live interviewers.

However, the majority of national polls show Trump trailing Clinton by wide margins. A new ABC News/Washington Post poll shows Clinton with a 12-point lead over Trump among likely-voters. According to the most recent CNN Poll of Polls, which averages the results from the four most recent publicly released national polls, Clinton leads Trump by 8-points among likely voters.

The businessman-turned-politician also told the crowd he was leading in the key swing states.

"We're up in Ohio, we're up in Iowa. We're doing great in North Carolina," he said. "I think we're doing great in Florida. I think we're really -- I think we're going to win Florida big."

Trump and Clinton are deadlocked in North Carolina and Ohio. A new Monmouth University poll shows Trump trailing Clinton by just one point in North Carolina, while polls from Quinnipiac University and Suffolk University show both candidates at 45% support among likely voters in Ohio. Clinton leads by a wider margin in Florida, where she leads with 48% support to Trump's 44% according to a Quinnipiac University poll.

Trump's campaign manager Kellyanne Conway said Sunday Trump was behind, about two weeks before Election Day.

"We are behind. She has some advantages," Conway told NBC's "Meet the Press," adding that Clinton "has a former president, happens to be her husband, campaigning for her; the current president and first lady, vice president -- all much more popular than she can hope to be. And she's seen as the incumbent."

Jason Miller, Trump's senior communications adviser, told CNN's Wolf Blitzer on the "Situation Room" Monday that the campaign is doing "fantastic."

"Let me tell you where he's behind. He's behind in Pennsylvania, slightly. He's behind slightly in Michigan. There's these blue states Mr. Trump is putting into play where we get zero credit for doing so," he said. "We're leading in places like Iowa, which has been blue the last couple of cycles. We're leading in Ohio. We're probably a tied race in North Carolina. We might be slightly ahead there. In Florida, I believe we're within the margin in that state. We're ahead with absentees at this moment.

He added: "We believe we're winning this race. Mr. Trump said that in his very last rally that he was in. That's the real reflection of where we are as a campaign."

CNN's Gregory Wallace, Adrienne Shih and Daniella Diaz contributed to this report.

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