US Republican presidential candidate Mitt Romney has criticised Barack Obama's supporters as people who live off government handouts and do not "care for their lives".

In a video, filmed secretly at a fundraising event, Mr Romney also said President Obama's supporters - almost half of voters in the US - did not pay taxes.

The video was the latest setback for his campaign, which is struggling with low poll numbers and reports of infighting.

Mr Romney hastily called a news conference in Costa Mesa, California, to respond to the video.

He said his comments were not well-stated, but he did not back away from them.

The video was shot with a hidden camera as Mr Romney spoke to potential donors at a private event earlier this year.

It was posted online yesterday by the liberal magazine Mother Jones.

"There are 47% who are with him (Obama), who are dependent upon government, who believe that they are victims, who believe the government has a responsibility to care for them," Mr Romney is heard saying on the video.

He also said the 47% did not pay taxes.

The video gave the Obama campaign a chance to return to a popular theme - that multi-millionaire Mr Romney is an out-of-touch elitist.

"It's not elegantly stated. Let me put it that way," Mr Romney said in response.

"I'm sure I could state it more clearly and in a more effective way than I did in a setting like that."

However, Mr Romney stuck by his video-taped remarks, saying it was a message that he would continue to carry in the run-up to the 6 November presidential election.

"Frankly, my discussion about lowering taxes isn't as attractive to them and therefore I'm not likely to draw them into my campaign as those in the middle," he said.

"This is really more about the political process of winning the election and of course I want to help all Americans have a bright and prosperous future and I'm convinced that the president's approach has not done that and will not do that."

Mr Romney has slipped in polls in the past two weeks as the selection of running mate Paul Ryan and the Republican National Convention failed to make much of a mark with voters.

A Reuters/Ipsos survey yesterday taken over the previous four days showed Mr Romney trailing Mr Obama by 5%.

In the new video, Mr Romney said he did not need to concern himself with Obama supporters.

"My job is not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives. What I have to do is convince the 5 to 10% in the centre that are independents," he said to potential donors.

The tape brought back memories of controversial remarks that then-candidate Mr Obama made at a fundraiser during his 2008 campaign when he said that white rural voters "cling to guns or religion".

Yesterday, the Obama campaign tried to take advantage of Mr Romney's comments.

"It's shocking that a candidate for president of the United States would go behind closed doors and declare to a group of wealthy donors that half the American people view themselves as 'victims'," Jim Messina, Mr Obama's campaign manager, said in a statement.

"It's hard to serve as president for all Americans when you've disdainfully written off half the nation," he said.

Mr Romney's campaign said the Republican is concerned about US citizens who are poor and unemployed.

"Mitt Romney wants to help all Americans struggling in the Obama economy," Mr Romney's campaign communications director Gail Gitcho said.

Mother Jones did not say when or where the video was taken to protect the identity of the person who recorded it.

It did say Mr Romney's remarks had been made at some point after he clinched the Republican presidential nomination in April.

Mr Romney also discussed with donors his strategy for appealing to undecided or independent voters by stressing disappointment with Mr Obama's policies.

"Those people that we have to get, they want to believe they did the right thing, but he just wasn't up to the task. They love the phrase that he's 'over his head'," Mr Romney said in the video.

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