Melissa Nann Burke | The Detroit News

Republican challenger John James apologized Monday for a "terrible mistake" — the appearance of a swastika in footage included in his recent Senate television ad.

In a brief shot, roughly 10 seconds into the ad, a swastika appears tacked to a bulletin board in a hallway of an unidentified school. It wasn't clear if it was part of a school history project or something else, but the campaign said it was from stock footage.

Democrats and liberal groups complained that James, a Farmington Hills businessman and Iraq War veteran, was promoting a symbol of hatred as he seeks to unseat incumbent Democratic Sen. Debbie Stabenow of Lansing, who is running for a fourth term.

James said he was taking responsibility for the oversight, since he approved the commercial whose run was set to end Monday. It shows his philosophy of admitting an error, fixing it and moving on, he said.

"We should have caught this error and we didn’t, and there’s no excuse," he said at a Monday afternoon press conference where he also unveiled a new ad to replace the "Ready to Serve" commercial that included the stock footage.

"I’m responsible for everything that our team does and fails to do. And I will do everything in my power to make sure this never happens again.

“As I’ve said before, I love everyone and I denounce hatred and bigotry in all of its forms.”

But Democrats were not giving James the benefit of the doubt.

"The sad reality is nobody would be assuming that this is anything other than an unfortunate coincidence, except for the fact that Donald Trump is president, and he has given aid and comfort to the kind of people who gravitate toward this symbol of hate," said Brandon Dillon, chair of the Michigan Democratic Party.

James complained that it was "low" for liberals and Democrats to imply that a combat veteran who fought for freedom on the battlefield would also back racism.

"I have a message of hope and I have a message of love," he said at the press conference, which aired on Twitter, about four hours following his last debate with Stabenow.

The Detroit News confirmed the clip was from stock footage, finding the exact same hallway clip on another site.

Melissa Nann Burke

The 37-year-old African-American also showed a new television ad set to start Tuesday that describes how his father grew up in the Jim Crow South, persevered over racism and how James learned his dad's lessons of "faith, service and love of country." The commercial ends with James saying, "We shall overcome."

But the liberal group Progress Michigan questioned how such a symbol of hate speech made it into a professional campaign ad, which was released Oct. 2.

“Making sure symbols of hate speech and genocide aren’t in your campaign ads should be a pretty basic thing to figure out, but apparently not for John James,” said Lonnie Scott, executive director of Progress Michigan.

“His team is either too lazy to spot check their ads, or they’re willfully pushing out this type of imagery. Either way, it’s a problem and shows James’ lack of preparedness for the United States Senate.”

Detroit News Staff Writers Jonathan Oosting and Leonard N. Fleming contributed