NASHVILLE (AP) — Democratic U.S. Senate candidate Phil Bredesen has written his city a six-figure check and removed his properties from a state program that provided him $520,600 in property tax breaks since 2011 for producing hay, The Tennessean reports.

The newspaper also reports that the former governor's Republican opponent, U.S. Rep. Marsha Blackburn, didn't disclose a $100,000 line of credit to repair a South Carolina house she co-owns, and accrued $2,600 in late property tax penalties on the house since 2014.

Each instance is drawing criticism from political interest groups of the opposing party, as the open race to succeed Republican Sen. Bob Corker heats up and attacks increase.

Bredesen had four of his parcels, totaling about 80 acres, removed from Tennessee's Greenbelt program and paid Nashville's government $181,700 in rollback taxes last month, reducing his tax savings from the program to $338,900. Rollback taxes aim to recoup some taxes lost by local governments, according to a 2009 report by the Tennessee Advisory Commission on Intergovernmental Relations.

Greenbelt beneficiaries can qualify based on three land uses: forest, open space or agriculture, the most common use and the one in Bredesen's case. With the break, the value of a property is assessed based on land use instead of market value.

Campaign spokeswoman Alyssa Hansen said there's nothing to hide, since Bredesen's land produced hay in legal compliance with the tax break that is open to all Tennessee taxpayers. Since 2011, Bredesen paid $478,200 in property taxes on those parcels.

"Gov. Bredesen is not going to apologize for being a successful businessman and entrepreneur who owns property," Hansen said.

In Blackburn's case, campaign spokeswoman Abbi Sigler said the line of credit regarding her Daufuske Island, South Carolina house was "used to renovate the personal home following storm damage."

Members must disclose lines of credit under U.S. House rules; However, lawmakers are sometimes given the opportunity to update the records.

"Members must report any mortgage, home equity loan, or home equity line of credit on any property that is personal - even if the property did not generate any income - if the liability totaled more than $10,000 at any point during the reporting period," according to a House ethics committee instruction guide on financial disclosures for the 2017 calendar year.

House members who "knowingly or willfully" omit information from financial disclosures could face criminal or civil penalties: up to a $59,000 fine or up to one year in prison, according to the House instruction guide.

Sigler did not respond to a question about Blackburn's failure to pay the house's property taxes on time.