Democratic Senate candidate Alexi Giannoulias of Illinois insisted Sunday that he did not know the extent of bank customers’ criminal activity when he was a senior loan officer at Broadway Bank.

Giannoulias, the state treasurer, faced off against his GOP opponent, Rep. Mark Kirk, in a debate Sunday on NBC’s “Meet the Press.”

Moderator David Gregory asked both Giannoulias and Kirk about inconsistencies in their personal biographies. He started with Giannoulias, focusing on his time at Broadway Bank. Republicans have tagged Giannoulias as a mob banker over loans given to organized crime figures.

“We didn’t know the extent of that activity,” Giannoulias said. Kirk responded with a list of individuals who had gotten loans from the bank and were convicted of felonies. He highlighted the loans for which Giannoulias had been the senior officer.

Giannoulias has continually faced questions about the business dealings of his family’s bank, being run by federal regulators since late April, during his Senate campaign. He maintained after the show that he was not backtracking.

“As we’ve said, if you look at every statement we’ve made over the last few years, we knew there were rumblings of problems,” the Democrat told reporters. “These weren’t loans I was intimately involved in, these weren’t relationships that I brought to the bank. Nothing has changed.”

When asked by Gregory about when he left the bank, Giannoulias said during the debate that there have been “no inconsistencies.” Though he had been described as leaving the bank in 2005, the Democrat explained that he only left day-to-day activities and continued to work there in 2006. The difference is significant because he received a tax break for his work in 2006, and he said he would donate the money to charity.

Gregory also revisited the inconsistencies revealed this year concerning Kirk’s military service with the Naval Reserve. Kirk claimed to have received an award individually that actually went to his entire unit and to have served in operations that he wasn’t a part of.

“I made mistakes with regard to my military misstatements,” Kirk said. “I was careless. I learned a very painful and humbling lesson.”

The debate covered a variety of policy issues but focused on the economy and tax cuts. Kirk said he would have extended the 2001 and 2003 tax cuts, even though he said in 2004 that the cuts should not be made permanent. He would not commit to supporting a budget proposal by Rep. Paul Ryan (R-Wis.) but said he would offer his own proposal.

“I have my own cuts, which I want to put forward,” he said. “For example, sell off big parts of the Tennessee Valley Authority, the Southeastern Power Administration. We should consolidate deep home maintenance at the Department of Defense. We should have a lawsuit reform, which the [Congressional Budget Office] says would save at least the federal government $54 million.”

In an interview with the Chicago Tribune’s editorial board a week ago, Giannoulias did not name any spending he would have cut at the federal level. In this debate, he said he would have voted against an omnibus spending bill and would be interested in the recommendations by the president’s deficit commission, which are expected in December.

Both campaigns claimed victory in the debate.

“Congressman Kirk’s comments about being a fiscal conservative are completely untrue, and it was another whopper for him to keep on saying that he’s a fiscal hawk,” Giannoulias told reporters after the debate. “The truth is no one in this race has taxed more, spent more, borrowed more and lied more, and that’s a fundamental difference in this race and the point we’re trying to make today.”

The Kirk campaign fired back in its e-mail response. “Alexi Giannoulias reiterated his support for the same tax and spend policies promoted in Springfield and Washington and reminded voters that he took a $2.7 million tax break while supporting state and federal tax increases on the people of Illinois,” it said.

Kirk dodged a question from a reporter about whether he wrote, “I’m concerned we’re meat on the table for the next moderate victim,” in a 2009 memo to campaign adviser Eric Elk.

“A candidate writes so many memos on their BlackBerry so fast, I’ll get back to you,” he said.

With the rise of conservative candidates this cycle in states such as Nevada, Colorado and Delaware, Kirk acknowledged that he could be the lone GOP moderate in the 2010 class if elected.

“I agree with them on their fiscal conservatism. On my social moderate views, I probably won’t be agreeing,” he told reporters. “My job in the Senate will be to reach out to all 99 Senators and try to work with them on key issues.”

The two candidates will face off again in an Oct. 19 debate hosted by Chicago’s local ABC affiliate. First lady Michelle Obama will travel to her home state to help Giannoulias stump for the seat previously held by her husband, President Barack Obama. Female voters and independents are key voting constituencies in the race, which is locked in a dead heat.

“I know it’s going to be a huge boost for our core Democrats, for women, for African-Americans, so we’re really excited to have her,” Giannoulias said after the debate.