MINNEAPOLIS (AP) — Vice President Joe Biden, who will be in Florida as Republicans gather to nominate their presidential ticket, on Tuesday compared GOP critics of the Obama administration's Wall Street reforms to "squealing pigs."

Biden's comments showed he has no intention of softening his attack-dog rhetoric, despite widespread criticism of remarks he made last week in which he said presumptive GOP nominee Mitt Romney and other Republicans would put Americans "back in chains" in order to unshackle Wall Street.

Appearing before a raucous crowd in downtown Minneapolis, Biden said a Democratic-led Congress had approved a law reining in the Wall Street excesses that contributed to the nation's economic collapse four years ago. The Dodd-Frank law, which toughened financial-industry regulations after the 2008 meltdown, was approved despite strong objections from Republicans, including Romney, Biden said.

"Over the objections — where they sound like squealing pigs — over the objections of Romney and all of his allies, we passed some of the toughest Wall Street regulations in history," Biden said.

Although the economy remains sluggish and unemployment persistently high, Biden said that progress was being made under President Back Obama.

"Folks, the middle class has started to come back. They have been ravaged," he said.

That assertion led Romney spokesman Ryan Williams to retort: "Vice President Biden's claim that the middle class is 'coming back' couldn't be more out of touch with the reality. Whether it's high unemployment, falling incomes, soaring tuition costs, or rising prices, middle-class families are struggling in the worst economic recovery America has ever had."

Biden also said a budget plan offered by Romney and his running mate, Rep. Paul Ryan, R-Wis., was neither new nor courageous.

"What's bold about gutting Medicare and education to pay for tax cuts" for the rich? Biden asked. "We've seen this movie before, we know how it ends. It ends with the Great Recession of 2008. It ends with catastrophe."

Biden said Romney had flip-flopped on trade sanctions against China by once denouncing them as protectionism but now supporting them. The vice president pointed to Romney's former firm, Bain Capital, to criticize the Republican further on China policy.

"I wish he'd been that tough when companies owned by Bain were outsourcing thousands of jobs to China," he said.

The Obama campaign announced that Biden will be attending events in Florida on Monday and Tuesday, including a stop in Tampa on the convention's opening day. Obama won Florida four years ago, but Republicans are hoping the weeklong convention will help them recapture the key battleground.

After his speech in Minneapolis, Biden asked reporters, "Any of you going to Florida?" He added, "I'm going to be the speaker at the convention."