WASHINGTON — US President Barack Obama on Monday hit back at his likely Republican election foe Mitt Romney, who questioned whether he shared the notion that America is a uniquely virtuous nation.

At the weekend, Romney appeared to tap into the view, prevalent among the conservative grass roots, that Obama -- born in Hawaii of a white mother and Kenyan father -- somehow is different than mainstream Americans.

Asked about the comments during a press conference with the leaders of Mexico and Canada on Monday, Obama said the man he is likely to face in November's election was simply playing to the political gallery.

"It's still primary season for the Republican Party," he said, but then took aim at Romney's central argument.

"It's worth noting that I first arrived on the national stage with a speech at the Democratic Convention that was entirely about American exceptionalism and that my entire career has been a testimony to American exceptionalism."

"But, you know, I will cut folks some slack for now because they're still trying to get their nomination."

Then Illinois state lawmaker Obama's speech in Boston in 2004 extolled the "genius" of America, quoted the Declaration of Independence and called on Americans to reaffirm unique values.

Romney said during an event in Wisconsin at the weekend that when he traveled abroad he stood "a little taller, a little straighter, because I knew I had a gift that others didn't have, and that was I was American."

"Our president doesn't have the same feelings about American exceptionalism that we do," Romney told a conservative crowd.

"I think over the last three or four years, some people around the world have begun to question that."

American exceptionalism is a highly charged term, and sometimes means different things to different people, and is a particularly potent concept in conservative politics.

Generally, the term is said to be the notion that America has a unique historic mission, values and ideals, that are either endowed by God or enshrined in the Constitution that make it exceptional in the world.