US President Barack Obama's re-election campaign distanced itself on Tuesday from a joke by Hollywood veteran Robert de Niro about the prospect of a white First Lady returning to the White House.
The reaction came after Republican candidate Newt Gingrich slammed the jest, -- made by Democrat-supporting actor De Niro at a fundraising event with Michelle Obama -- as 'unacceptable'.
"We believe the joke was inappropriate," said the first lady's campaign press secretary Olivia Alair after Gingrich's comments triggered a tide of online argument about the joke.
Raging Bull star De Niro made the contested remark as he introduced Michelle Obama at a fundraising event on Monday in New York's trendy Greenwich Village district.
"Callista Gingrich. Karen Santorum. Ann Romney. Now do you really think our country is ready for a white first lady?" the actor said, referring to the wives of Republican candidates Gingrich, Rick Santorum and Mitt Romney.
"No" yelled one person as the crowd roared, while De Niro added: "Too soon, right?"
The joke played on the ubiquitous discussion four years ago about whether America was ready for its first black president, ahead of Obama's November 2008 election victory.
But Gingrich -- struggling in his campaign to win the Republican nomination to take on Obama in November -- took issue at a campaign stop on Tuesday, demanding an apology from the president.
"I do want to say one thing on behalf of both my wife, and on behalf of Karen Santorum and on behalf of Ann Romney, and that is I think Robert De Niro is wrong," the former House Speaker said on the campaign trail in Louisiana.
"I think the country is ready for a new first lady, and he doesn't have to describe it in racial terms." He added: "I call on the president to apologize for him."
De Niro insisted the comments were a joke.
"My remarks, although spoken with satirical jest, were not meant to offend or embarrass anyone -- especially the First Lady," he said in a comment forwarded by his publicist.