Democratic Party Chairman Bill Lynch is demanding that Republican Governor Carcieri disclose the names of any “corporate backers” paying for the radio ad campaign touting his tax-and-spending proposals.

There was no immediate response from the governor’s office, but state GOP Chairman Giovanni Cicione replied that “people who live in glass houses shouldn’t throw stones.”

State law prohibits corporate donations to campaign accounts, and limits individual contributions to $1,000 per year. But Carcieri, after closing out his public campaign finance account, is leaning on contributions from undisclosed donors to the nonpublic TransformRI to finance his radio ad campaign.

In a statement issued Tuesday, the day before House budget writers plan to unveil their version of a new state budget, Lynch called on Carcieri “to act in the interest of public transparency today and release the list of corporate donors who have given untold sums of money to Transform RI — the Carcieri front group that exclusively advocates the governor’s pro-big-business agenda.”

Said Lynch: “Rhode Islanders have a right to know which companies are behind or at least aiding the governor’s media blitz to cut corporate taxes at the expense of the middle class. … Who gave what and how much to push this corporate-tax giveaway?” Lynch asked.

Cicione fired back in a news release by calling on Democrats to disclose their own sources of funding.

“Rhode Island Democrats have a long history of ‘pay to play’ when it comes to State House access, and they don’t like it when the business community stands up for itself,” Cicione wrote. “To call on a nonprofit to disclose its donors flies in the face of free-speech protections that cover such entities.” According to its Web site, TransformRI is registered with the Internal Revenue Service as a 501(c)4, which means it is allowed to lobby and engage in campaign activity. Carcieri is the honorary chairman of the nonpublic organization, which, in recent weeks, began airing the ad featuring Carcieri’s voice urging Rhode Islanders to contact their legislators in support of the governor’s tax-cut proposals.