WASHINGTON — Vice President Joe Biden, no stranger to gaffes, said Tuesday at a campaign event in Charlotte, N.C., that the middle class has “been buried the last four years.”

The presumed slip — Biden and President Barack Obama have led the country for nearly the past four years — came as Biden charged that Republican presidential challenger Mitt Romney’s tax plan would result in a tax increase for middle-class families.

“How they can justify raising taxes on the middle class that’s been buried the last four years?” Biden said. “How in lord’s name can they justify raising their taxes and these tax cuts? Look folks, we’ve seen this movie before.”

Republicans and the Romney campaign pounced immediately, saying they agreed with what they called Biden’s “stunning admission.”

From his Twitter account, Romney said he agreed with Biden that “the middle class has been buried the last 4 years, which is why we need a change in November.”

“We agree,” said his running mate, Rep. Paul Ryan, in Iowa. “That means we need to stop digging by electing Mitt Romney the next president of the United States.”

Biden’s remarks came a day before Obama and Romney face off in their first debate. He retooled his words at a later event in Asheville, N.C., saying, “The middle class was buried by the policies that Romney and Ryan have supported.”

Democrats accused Republicans of taking Biden’s remarks out of context, but they served to call attention to the standing of the middle class under Obama — incomes are down and poverty rates are up — as well as to Biden’s history of putting his foot in his mouth.

Biden, who will debate Ryan on Oct. 11 in Kentucky, has had a history of misstatements and missteps that have sent his handlers scrambling and the White House seeking to impose damage control.

Among his gaffes:

—He once said that Franklin D. Roosevelt went on television when the stock market crashed, apparently forgetting that Roosevelt was not yet president in 1929, and television had not been invented.

—He once asked a man in an audience to stand up so people could see him. The man was in a wheelchair.

—Talking about immigration trends, he once said, “You cannot go to a 7-Eleven or a Dunkin’ Donuts unless you have a slight Indian accent. I’m not joking.”

—At the start of his own campaign for the 2008 Democratic presidential nomination, Biden called Obama “the first mainstream African-American who is articulate and bright and clean and a nice-looking guy.”

—In 2009, Biden told a national TV audience that he was urging his own family to stay off commercial airliners and out of subways for fear of catching swine flu, a statement that went further than any from the Obama administration. It drew a quick rebuke from the travel industry and an apology from the White House.

—And in August, he lambasted Romney’s stance on financial regulation, telling a largely African-American audience in Virginia that Romney “is going to let the big banks once again write their own rules. Unchain Wall Street,” he said, adding, “He is going to put y’all back in chains.” The remarks prompted Romney to accuse the White House of fostering “division and anger and hate.”