Senior Obama campaign adviser Robert Gibbs said on Sunday that he would not be "lectured" about running a negative campaign while GOP hopeful Mitt Romney continued to use a "right-wing nut job" like so-called birther Donald Trump.

During an interview on Fox News, host Chris Wallace noted that Romney had been accusing President Barack Obama of waging "a campaign of division and anger and hate."

"I'm not going to get lectured by Mitt Romney or anybody on the Romney campaign about the tone of this campaign," Gibbs explained. "This is a guy that's flown all over the country saying he's not sure whether the president believes in America."

"[Romney is] auctioning off dinners with birther-in-chief, right-wing nut job Donald Trump, who still questions whether or not the president of the United States was born in America."

"I'm happy to listen to charges and counter charges," he added. "But the notion we're going to get lectured by Mitt Romney and his campaign about running a positive campaign, that's a pill far too big to swallow."

Only a day before appearing at a Las Vegas fundraiser with Romney in May, Trump said "nothing's changed my mind" about doubting the president's citizenship, and suggested the president was "born in Kenya and raised in Indonesia."

As recently as last week, the billionaire reality star hinted that he would have a "wild" role at the Republican National Convention.