Democrat White House hopeful John Kerry has accused President George W Bush of keeping secrets from US voters, exactly one week before the election.
John Kerry accused the president of ignoring bad news from Iraq
Mr Kerry berated his rival for not discussing a huge cache of missing weapons in Iraq and queried what else he was not talking about.
Vice President Dick Cheney tried to fend off the attack while Mr Bush aimed fire at his opponent's tax pledges.
With the race still so close, the final campaigning is getting yet more bitter.
In a second day of blistering attacks, Mr Kerry again focused on reports about the 350 metric tons of explosives that went missing after the US-led invasion of Iraq.
"What did the president have to say about the missing explosives? Not a word. Complete silence," Mr Kerry said in Green Bay.
He then quoted a Washington Post report that the Bush administration would seek new funding for military operations in Iraq and Afghanistan.
"We have learned that the president wants an additional $70bn of your money by early next year for Iraq and Afghanistan, bringing the total cost to $225bn," Mr Kerry said.
"Mr President, what else are you being silent about? What else are you keeping from the American people? How much more will the American people have to pay?"
The non-partisan organisation Factcheck.org says Mr Kerry has consistently overstated the amount actually spent on the Iraq war to date.
In response, Mr Cheney said it was not yet clear the explosives had not been stolen from the facility before US troops arrived.
"John Kerry doesn't mention that. Nor does he mention the 400,000 tons of weapons and explosives that our troops have captured and are destroying... 400,000 tons of weapons and explosives that would be in the hands of Saddam Hussein who would still be sitting in his palace," he said, according to AFP.
Mr Kerry charges there is no evidence the weapons had already been stolen.
Meanwhile, Mr Bush took aim at Mr Kerry's pledges to raise tax on those earning over $200,000 a year, saying it would hurt small business owners.
"My opponent believes the economy grows by growing the size of the federal government. I believe the economy grows by growing the size of the coffers of small businesses," Mr Bush told supporters.
Mr Bush focused on the economy and family needs at the day's first rally
Mr Kerry left Wisconsin, to travel to Nevada, New Mexico and Iowa on Tuesday, while Mr Bush was spending most of his day in Wisconsin.
All are seen as swing states that could be won by either candidate and may make the difference in the overall election.
Correspondents say that Wisconsin, with its 10 electoral votes, is becoming as keenly fought over as "the big three" swing states of Florida, Ohio and Pennsylvania.
The Kerry campaign announced on Tuesday that rocker Bruce Springsteen would appear with Mr Kerry at rallies in Wisconsin and Ohio later this week.
California Governor Arnold Schwarzenegger will campaign with Mr Bush on Friday in Ohio.
Nationally, opinion polls show Mr Bush with a slight - but statistically insignificant - lead over Mr Kerry, though that position is reversed in some of the battleground states.
And in a sign that the election will remain unpredictable, new surveys indicate that voters in what had expected to be a safe Democrat hold in Hawaii may yet pick Mr Bush, while it may also be close in Arkansas - previously thought to be solidly in the Republican column.