NORTH CHARLESTON, South Carolina — As Hillary Clinton prepared to return to the Palmetto State Wednesday, her top rival for the Democratic nomination was “feeling the Bern.”

Sen. Bernie Sanders’ campaign Tuesday night decided to move an event planned for Sunday in Charleston to a larger venue after more than 1,000 signed up to attend on the campaign’s website.

“The response in South Carolina has been tremendous,” said Phil Fiermonte, the campaign’s national field director. “The interest in Bernie and his message about rebuilding our middle class is resonating in South Carolina like it is in other states around the country.”

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On Monday, the executive board of the South Carolina AFL-CIO passed a resolution supporting Sanders’ candidacy. “We firmly believe that Senator Bernie Sanders is the strongest candidate articulating our issues,” the labor union wrote, calling on “union members and working people everywhere to unite behind Bernie Sanders and elect the President America’s workers desperately need.”

The state council also called on the national AFL-CIO to endorse Sanders. But Michael Podhorzer, the political director of the national labor federation told msnbc that AFL-CIO bylaws prohibit state councils from making endorsements or recommending them. Close video Sanders continues to climb in polls Sen. Bernie Sanders continues his upward climb in New Hampshire, where he’s taking 31 percent of likely Democratic voters, according to a Suffolk University poll. Sen. Bernie Sanders continues his upward climb in New Hampshire, where he’s taking 31 percent of likely Democratic voters, according to a Suffolk University poll. share tweet email Embed

Podhorzer and other AFL-CIO officials told reporters at a briefing Tuesday in their Washington, D.C., headquarters that the endorsement process would be forthcoming, and declined to offer much specific praise for Sanders or any other candidates.

And though they’re fighting President Obama’s trade agenda tooth and nail, they did not rule out the possibility of endorsing Clinton, even if she does not actively oppose the trade deal.

“We feel that there is no perfect candidate,” said Podhorzer, who added that the AFL-CIO’s members would ultimately make a call about endorsements, likely later this year.

The moves come as Sanders has surged in recent polls, especially in New Hampshire. A Suffolk University poll showed Sanders just 10 points behind Clinton in the Granite State and beating her among men in the state by three percentage points.

Meanwhile, a Morning Consult poll, which was partially conducted online, found Sanders just 12 points behind Clinton.

Bernie-mentum could even be found among the Clinton supporters at her event Tuesday at an apple orchard in Concord, New Hampshire.

Donald Giguere, an activist involved with the Tilton Democrats came to the event wearing an Obama ’08 baseball cap. He worked hard for the Clinton challenger then and held house parties for Howard Dean in 2004, who remains one of his favorite politicians.

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Giguere said he’s “definitely with Hillary” this time, and was pleased with Dean’s endorsement of the former secretary of state.

But when asked about Sanders, he acknowledged his support for Clinton is not absolute. “He’s probably where my heart is,” Giguere said of Sanders, before adding that Clinton is more likely to win. “A lot of my friends are pushing for Bernie.”

Mason Twombly and Adelaide Murray, both students a University of New Hampshire, said many of their friends are supporting Sanders as well. “I feel like Hillary Clinton has a better shot at the presidency,” said Twombly.

Clinton still has the clearest shot at a nomination of any candidate in either party, and even many Sanders supporters don’t actually think he should be president.

Clinton aides insist they’re not surprised by Sanders’ upswing, saying they always expected a competitive primary.