President Trump’s re-election campaign is deeming Vermont Sen. Bernie Sanders the indisputable frontrunner in the Democratic primary, as polling shows the Democratic socialist rising in Iowa just weeks before the caucuses kick off the nominating season.

“There is no mistaking that Bernie Sanders has to be considered the frontrunner now,” a senior Trump campaign official told Fox News on Monday.

BERNIE SANDERS TOP PICK FOR DEMOCRATIC NOMINATION IN LATEST IOWA POLL AHEAD OF FEBRUARY CAUCUS

The Des Moines Register over the weekend published the results of its latest poll showing Sanders leading in the state. That poll has Sanders with 20 percent, Massachusetts Sen. Elizabeth Warren at 17 percent, former South Bend, Ind., Mayor Pete Buttigieg at 16 percent and former Vice President Joe Biden at 15 percent.

The official indicated the Des Moines Register poll, combined with Sanders’ response to the situation in Iran, is why there has been an uptick in attacks on Sanders from the president and his campaign.

“We try to engage with the Democratic candidates as they present themselves as opportunities,” the aide said. “It just so happened that for a long time Joe Biden was a gaffe a minute and we focused a lot on him. But this whole episode with Iran revealed just how dangerous [Sanders] would be if he were somehow to become president.”

Elaborating on Sanders, the official said: “He has shown himself to be an apologist for the Iranian regime and someone who’s first instinct is to appease states that support terrorism. It’s dangerous. Highlighting that was necessary.”

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The campaign’s elevation of Sanders could be strategic and a reflection of who the campaign would prefer to compete with in a general election. Jim Messina, former President Barack Obama’s 2012 campaign manager, recently told Politico: “If I were a campaign manager for Donald Trump and I look at the field, I would very much want to run against Bernie Sanders.”

But the Trump campaign insists that it has “no preference” who the Democratic nominee will be.

“It doesn’t matter who it is,” the senior Trump official said. “The proposals the eventual nominee will have will be so liberal and so extreme as to be outside the mainstream. It truly does not matter to us which one is carrying the banner.”

On Twitter on Monday, Trump appeared to be fanning the flames of the rivalry between Sanders and Warren, referencing a report that Sanders’ campaign has volunteers pushing anti-Warren talking points in Iowa.

Trump tweeted that Sanders’ “volunteers are trashing” Warren.

“Elizabeth is very angry at Bernie. Do I see a feud brewing?” Trump tweeted.

Sanders, meanwhile, took a swipe at Trump as he responded Monday to the news that Sen. Cory Booker, D-N.J., was bowing out of the race.

"Thank you @CoryBooker for running an inspiring campaign to make this the country based on love and justice we know we can become. I look forward to working together to defeat Trump, end his hatred, and lift up working people everywhere," he tweeted.