Republican Senate nominee Tommy Thompson said Wednesday that he would not release his personal tax returns as part of his bid for office.

“When I was governor and I was employed [by] the people of the state of Wisconsin, I released my tax returns. But I’ve been in the business world and the question is, am I going to release my tax returns? The answer is no,” Thompson said in his first media availability since winning a closely contested four-way primary Tuesday.

When pressed again, Thompson pushed back: “No. The answer is N-O. What part don’t you understand?”

The issue of releasing tax returns has been elevated to national prominence by presumptive Republican presidential nominee Mitt Romney’s refusal to publicize his personal tax returns dating back further than two years. His pick for vice president, Rep. Paul Ryan (Wis.), has said that he was required to present more years of returns as part of his vetting process but will publicly disclose two just like Romney.

Thompson’s comments Wednesday came in a question-and-answer session with reporters in front of employees on the manufacturing floor of HUSCO International in Waukesha. Thompson’s Democratic challenger, Rep. Tammy Baldwin (D-Wis.), has released 10 years of state and federal tax returns. Before Tuesday’s primary, Baldwin challenged all of the GOP’s potential candidates to release their returns. Only conservative businessman Eric Hovde did so, allowing reporters to review hundreds of pages of federal returns, according to an Aug. 10 account in the Milwaukee Journal Sentinel.

“We have complied with all financial disclosures, and upon our victory in November will make additional disclosures,” said Thompson campaign spokesman Brian Nemoir.