WASHINGTON (Reuters) - Republican presidential candidate Mitt Romney dismissed supporters of President Barack Obama - almost half of U.S. voters - as people who live off government handouts and do not "care for their lives," in a potentially damaging video.

The video, taken secretly at a fundraising event for the former private-equity executive, was the latest setback for his campaign, which is struggling with low poll numbers and reports of infighting.

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 Romney spoke to potential donors at a private event earlier this year. It was posted online on Monday by the liberal magazine Mother Jones.

"There are 47 percent 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," Romney is heard saying on the video. He also said the 47 percent did not pay taxes.

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

"It's not elegantly stated. Let me put it that way," 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," he told the news conference in California.

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

The video added to Romney's problems as he tried to retool his campaign message with more specifics on policies after reports of internal disarray.

He 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 on Monday taken over the previous four days showed Romney - often painted by rivals as an out-of-touch elitist - trailing Obama by five percentage points.

In the new video, 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 percent in the center that are independents," he said to potential donors.

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

On Monday, the Obama campaign tried to take advantage of 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, 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.

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

"Mitt Romney wants to help all Americans struggling in the Obama economy," Gail Gitcho, Romney's campaign communications director, said in a statement issued in response to a request for comment.

OBAMA SUPPORTERS "PAY NO INCOME TAX"

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

In the video, the former Massachusetts governor accused Obama supporters of paying no income taxes. "These are people who pay no income tax," he said. "Forty-seven percent of Americans pay no income tax."

Romney has been criticized for not releasing more than two years' worth of tax returns.

Republican National Committee Chairman Reince Priebus jumped to Romney's defense.

"I think that we are entering into a dependency society in this country, that if we don't break that up, I think that's going to be very hard for us to compete in the world," he told CNN. "I don't think the candidate's off message at all."

Romney also discussed with donors his strategy for appealing to undecided or independent voters by stressing disappointment with 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,'" Romney said in the video.