Romney voices anger at Newt's 'repulsive slur' on '

Republican White House hopeful Newt Gingrich accused his rival Mitt Romney of being anti-immigration during a fractious debate in Florida.

The former Massachusetts governor labelled Mr Gingrich's claim "repulsive", adding: "That's simply inexcusable. My father was born in Mexico. I'm not anti-immigrant."

Mr Romney attacked his rival for running adverts calling him anti-immigrant: "It's simply the kind of over-the-top rhetoric that's characterised American politics too long. I think you should apologise for it and recognise that having differences of opinions does not justify labelling people with highly charged epithets."

Mr Gingrich, a former speaker of the House of Representatives, said Mr Romney's immigration policy would result in the deportation of grandmothers and grandfathers who are in the US illegally.

Mr Romney ridiculed Mr Gingrich's plans to build a base on the moon, saying: "If I had a business executive come to me and say I want to spend a few hundred billion dollars to put a colony on the moon, I'd say, 'You're fired.'"

In turn, Mr Gingrich raised questions about his rival's wealth, estimated at up to $250 million (£159 million). "I don't know of any American president who's had a Swiss bank account," he said.

It was the last Republican debate before Tuesday's pivotal Florida primary. Polls indicate a close race between the pair, with ex-senator Rick Santorum and Texas congressman Ron Paul trailing.

Mr Gingrich's victory in the South Carolina primary last weekend has put pressure on Mr Romney, long the frontrunner.