Media playback is unsupported on your device Media caption Video courtesy of www.motherjones.com

A new secret video clip has emerged of remarks by Republican candidate Mitt Romney, saying the Palestinians are committed to Israel's destruction.

He tells donors the Middle East will "remain an unsolved problem... and we kick the ball down the field".

The video is from the same event as a clip released on Monday, in which Mr Romney says almost half of Americans "believe that they are victims".

The leak comes seven weeks before the US presidential election.

Speaking on Fox News on Tuesday, Mr Romney stood by his comments, leaked on Monday, that 47% of Americans who do not pay income tax support President Barack Obama and would never vote for him.

"Those that are dependent on government and those that think government's job is to redistribute, I'm not going to get them," Mr Romney said, describing redistribution as "an entirely foreign concept".

'Chicago dirty bomb'

The new footage was posted on Tuesday on the website of the liberal investigative magazine Mother Jones, which said it was taken at a fundraiser in May in Boca Raton, Florida.

Mr Romney is shown saying that Palestinians are "committed to the destruction and elimination of Israel".

"The Palestinians have no interest whatsoever in establishing peace," he says, adding that "the pathway to peace is almost unthinkable to accomplish".

Analysis Mitt Romney's unguarded and undiplomatic remarks may reinforce the perception that he is an ingenue in the art of foreign affairs, with harsher views than he dare express in public. Still, what he has said is more likely to provoke reactions in the region he is talking about than at home, where many conservatives may share his views. It is still his suggestion that nearly half the American people he seeks to represent are losers living off the government, that will continue to resonate here. Again, it is about image - he has played into the hands of Democrats who want to portray him as rich and out of touch. It has been widely reported that there has been panic in his camp because of the post-convention Obama bump in the opinion polls. Under 50 days away from polling day, no candidate wants to be hastily refocusing their campaign amid a barrage of stories about catastrophic gaffes.

But Chief Palestinian Negotiator Saeb Erekat told Reuters news agency that Mr Romney was wrong to accuse the Palestinians of not seeking peace.

"Only those who want to maintain the Israeli occupation will claim the Palestinians are not interested in peace," he said.

In another clip, the former Massachusetts governor is shown discussing Iran's nuclear programme, and warning that America itself could come under attack.

"If I were Iran - a crazed fanatic - I'd say let's get a little fissile material to Hezbollah, have them carry it to Chicago or some other place, and then if anything goes wrong, or America starts acting up, we'll just say, 'Guess what? Unless you stand down, why, we're going to let off a dirty bomb'."

On Monday, Mother Jones posted another clip from the same fundraiser in which Mr Romney disparages those who would vote for his Democratic rival, President Barack Obama.

Not 'elegantly stated'

The Republican candidate is shown saying that the 47% of Americans who back the president do not pay income tax and would never vote for Mr Romney.

"There are 47% who are with him [Mr Obama], who are dependent upon government, who believe that they are victims, who believe the government has a responsibility to care for them, who believe that they are entitled to health care, to food, to housing, to you-name-it."

Mr Romney said in the video that his role "is not to worry about those people. I'll never convince them they should take personal responsibility and care for their lives."

Media playback is unsupported on your device Media caption Extract of Mitt Romney secret recording: "They'll vote for this president no matter what"

In a late-night appearance on Monday, the Republican candidate said those remarks were not "elegantly stated", but did not retract them.

The Obama campaign was quick to pounce.

"It's hard to serve as president for all Americans when you've disdainfully written off half the nation," Jim Messina, Mr Obama's campaign manager, said in a statement.

The video clips provided to Mother Jones are said to have been filmed at a $50,000 (£31,000) a head fundraiser at some point after Mr Romney became the presumptive Republican nominee.

Romney strategy rethink

The pictures are blurred out with the exception of his face, and no attendees are visible.

Who pays US income tax? The US federal government runs off two kinds of taxes: payroll taxes, which fund benefits such as Social Security, and income taxes, which largely fund the rest of the federal budget. In 2011, the Tax Policy Center studied the tax liability of US households: 53.6% paid income taxes, 46.4% did not

28.3% paid payroll taxes but not income taxes

10.3% were elderly and retired and were not taxed on Social Security benefits

6.9% did not pay any tax with household incomes of less than $20,000 (£12,300) The majority of those who pay payroll but not income tax do so because of tax benefits for the elderly, families with children and low-income earners.

Also on Monday, Mr Romney's campaign unveiled a significant reworking of its strategy less than two months before election day.

Until now his message to voters has largely consisted of repeated attacks on President Obama's economic record.

Campaign advisers told the US media on Monday that Mr Romney would speak more specifically about his budget plans and tax policy.

The videos bookended a difficult 24 hours for the Romney campaign. On Sunday, a lengthy Politico story detailed apparent divisions and indecision within the campaign.

A series of opinion polls at the end of last week showed Mr Romney trailing Mr Obama both nationally and in several swing states.

The two men square off in the election on 6 November, but early voting begins soon in several states.