A new political ad produced by a fringe nonprofit group uses footage of Israeli prime minister Benjamin Netanyahu warning about Iran's nuclear program in order to attack President Barack Obama.

The group, Secure America Now, has spent $400,000 to air the ad in heavily Jewish districts in south Florida, including Miami, West Palm Beach and Fort Myers, Politico reported.

"The fact is that every day that passes, Iran gets closer and closer to nuclear bombs," Netanyahu says in the ad. "The world tells Israel, 'Wait, there's still time.' And I say, 'Wait for what? Wait until when?'"

The ad concludes with the tagline, "The world needs American strength. Not apologies."

One of the nonprofit group's founders, John McLaughlin, was an adviser to Netanyahu's Likud party in 2006 and has also worked for former California governor Arnold Schwarzenegger. As a 501(c)4 group devoted to "social welfare", the group is not required to disclose its donors.

The ad is the latest in a series of appearances by Netanyahu in the heated US presidential election. The prime minister made a point of being photographed with Republican challenger Mitt Romney on his visit to Israel in July and praised the candidate's views on Iran.

In a Jerusalem press conference on the 9/11 anniversary, Netanyahu criticized the Obama administration's refusal to notify Iran of a "red line" that would trigger an attack on its nuclear facilities. Complaints by the prime minister's office about Obama declining a meeting at the UN next week have been eagerly used by Republicans in attacks on the president.

Netanyahu's remarks in the ad are sentences taken out of order from the 11 September press conference, which followed a meeting with the Bulgarian prime minister.

The likelihood that the ad will have an impact on the US election is extremely small. Netanyahu, who has been fighting the erosion of his domestic political coalition, is a polarizing figure among Jewish voters, who support the president by a large 69-25 margin, according to the latest poll by the American Jewish Committee.

A single-digit minority of Jewish voters say Israel policy is the most important factor in determining their votes.

The president is also leading Romney in Florida, according to most polls, with one by Fox News this week giving him a five-point advantage, 49-44.

But the use of Netanyahu's remarks in an anti-Obama swing-state ad underlines the extent to which his unusually public attacks on the administration's policy have become intensely politicized, and could have deeper consequences for his relationship with the White House in the apparently likely event that Obama wins in November.

Previous ads produced by Secure America Now include one from July called Are We Safer? that uses graphic footage of the 9/11 attacks and an actor warning that "our president apologizes for America".

The International Atomic Energy Agency reported last month that Iran had installed more than 2,100 centrifuges inside a fortified underground facility known as Fordow and continues to produce nuclear fuel.

Only about a third of the centrifuges are operating, however, and the program was not close to producing a sufficient quantity of sufficiently enriched fuel to produce a weapon, according to inspectors, who continue to have access to the site.