CHARLOTTE, N.C. - Vice President Joe Biden, criticizing Mitt Romney and Rep. Paul Ryan for a plan he said will raise taxes on the middle class, instead stepped on his campaign's message by saying the middle class has been "buried" over the last four years - the time President Obama has been in office.

"This is deadly earnest. How they can justify, how they can justify raising taxes on the middle class that has been buried the last four years, how in the Lord's name can they justify raising their taxes. We've seen this movie before," Biden said to a crowd of 1,000 at the Fillmore Charlotte.

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The Republican National Committee and the Romney campaign quickly pounced on a statement. The RNC circulated the clip and the Romney campaign called Biden's comments a "stunning admission."

"Vice President Biden made a stunning admission today and we couldn't agree more: the middle class has been 'buried' under the last four years of this President's policies. Under President Obama, the middle class has suffered from crushing unemployment, rising prices and falling incomes. They can't afford to be 'buried' for four more years. Mitt Romney and Paul Ryan will take our nation in a new direction and are offering exactly what hardworking families need - real reforms for a real recovery," Romney spokeswoman Amanda Henneberg said in a statement.

An Obama campaign official said Biden has said throughout his time on the campaign trail that the Bush administration was responsible for the burdens placed on the middle class.

"As the Vice President has been saying all year and again in his remarks today, the middle class was punished by the failed Bush policies that crashed our economy - and a vote for Mitt Romney and Paul Ryan is a return to those failed policies. With more than five million private-sector jobs created since 2010, the Vice President and President Obama will continue to help the middle class recover and move the nation forward," the campaign official said.

Nearly one month after the Democratic National Convention, Biden returned to Charlotte for the first time and tried to draw a contrast between Obama and Romney's positions on tax cuts for the middle class. Biden swiped at the GOP ticket for not being on the same message when it comes to middle class tax cuts, pointing to Romney's statement at a rally in Ohio last week where he said, "I admit this, [President Obama] has one thing he did not do in his first four years - he's said he's going to do in the next four years, which is to raise taxes."

"Then they come along and they say well we raised taxes on the middle class. How many times you hear Obama and Biden raise taxes on the middle class? Well even Romney had what we Catholics say an epiphany. Romney come out and said the following. He said, 'They have not raised taxes on the middle class.' But apparently Paul Ryan has not gotten the memo," Biden said to a crowd of over a thousand at the Fillmore Charlotte. "I'm serious. They know it. The President didn't raise taxes on the middle class. Yet, turn on the ads. We cut taxes for everyone in the middle class! Three thousand and six hundred dollars."

Biden, who was working off a teleprompter, struggled with pinpointing a vote Ryan made, stumbling when he tried to explain how it played out.

"They still say we really urgently want to deal with it now. Basic, I think my opponent said something like, you know, I don't know, he said something about he has regrets or I don't know, something he wished he hadn't voted that way. OK? I don't want to, I don't want to mis-, I don't want the press saying I misquoted him, but … he went back and said I did that but I kind of wish I didn't, whatever," Biden said.

Ryan has said before that he regrets certain votes on spending that he made when Republicans dominated Congress and President Bush was in office.

Biden is on his sixth trip to the battleground state of North Carolina and encouraged supporters to spread the word about voter registration, which ends Oct. 12.

"By the way, before I get started, I want to remind y'all of what you already know, but it's worth saying again and again: the deadline to register in North Carolina is Oct. 12. And if you're already registered or folks that, if you're not registered yet, there's folks at the door literally with clipboards, our team out there, who are willing to help you get that process going," Biden said. "The reason we're going to win North Carolina is we're going to have the best ground game you've ever seen in this state."

At the top of his speech, Biden apologized to the crowd for the hour delay in the event. Air Force Two was forced to circle in the air for more than 30 minutes before landing due to bad weather.

"As the traveling press can tell you, there are some queasy stomachs on our plane," Biden said at the start of the event. "We got off late because of weather and we got here and we had to make several passes before we landed. That's why we're late, I promise you we take you seriously. Blame it on the weather."

UPDATE: At an event at the University of North Carolina at Asheville, Biden clarified what he meant by saying the middle class has been "buried" and argued that it's the policies supported by Romney and Ryan that have put the middle class in this position.

"Folks, a lot of you have been through an awful lot these past few years, particularly your parents. As I said the middle class has been decimated. We lost 9 million jobs because of that Great Recession," Biden said. "The middle class was buried by the policies that Romney and then Ryan supported. As Bill Clinton said all they're suggesting now, when he was asked about this - and he's the best - he made a comment, he said what they're proposing is Bush economic policies on steroids. That's what this is. But folks, the middle class is coming back, it's coming back like Americans always come back. Your parents and all of you, you fought back, you didn't lose faith, you didn't give up, you got up. "