(CNN) - Hoping the proposal to suspend the gas tax will resonate with working class voters in Indiana and North Carolina, the Clinton campaign launched a last-minute ad in those states Monday that sharply attacks rival Barack Obama for not supporting the measure.
"What has happened to Barack Obama?" an announcer states in the new 30 second spot, among the campaign's most bruising to date.
"He is attacking Hillary’s plan to give you a break on gas prices because he doesn’t have one," the ad's announcer also says.
The ad comes on the heels of a weekend marked by heated back-and-forth between both campaigns over the issue. Obama's campaign launched an ad Sunday that called Clinton's proposal to suspend the gas tax a "classic Washington gimmick" and argues that oil companies will keep the extra proceeds from the suspension of the gas tax and will not pass the savings onto drivers.
The Clinton campaign countered that Obama is siding with the oil companies over hard working voters increasingly pinched by the price of gas.
UPDATE: Barack Obama's campaign released a response ad Monday afternoon that charges Clinton with offering "More of the same old negative politics."
“A war that should never have been waged. An economy in turmoil. Record prices at the pump. America held hostage to foreign oil," the ad's announcer states.
“Her hometown newspaper says she's taking the low road – her attacks do nothing but harm," the announcer also says. “The same old Washington politics won't fix our problems. We need honest answers... And a president we can trust."