The campaign debate over President Obama's "you didn't build that" remark raged on Wednesday even as Mitt Romney arrived in London for his overseas trip -- with Obama conducting damage control in a new TV ad and Romney's campaign hammering back with, "he said it, he meant it."

The president over the past several days has argued that Republicans twisted his words and took them out of context. While Romney claims Obama was talking about businesses when he said, "if you've got a business, you didn't build that," Obama now says he was actually trying to make the point that business owners "didn't build" roads and bridges -- something he had referred to earlier in the speech. 

The president was out with a new TV ad making that case, and refuting recent GOP ads. The ad shows Obama looking straight into the camera, saying: "Those ads, taking my words about small business out of context, they're flat-out wrong. Of course Americans build their own businesses." 

But the Romney campaign doubled down on its criticism, accusing Obama of trying to walk back what he said. 

"He said it, he meant it," the campaign said in a statement Wednesday morning. 

Read More: FOX News