Ben Carson has taken a commanding double-digit lead in Iowa, according to a new Republican presidential primary poll. 

Monmouth University released a survey Monday showing the retired neurosurgeon leading with 32 percent among caucus-goers. Trump registered with 18 percent. 

It's the latest in a series of recent polls showing Carson overtaking Trump in Iowa -- but 14 percentage points is his biggest lead to date. 

Carson's momentum in Iowa has fueled tensions on the campaign trail, with Trump criticizing Carson on immigration and other issues, while downplaying the latest Iowa polling. 

In the Monmouth University poll, Carson leads Trump by 9 points among self-described "very" conservative voters and 21 points among self-described "somewhat" conservative voters. 

The race in Iowa remains fluid, with just 19 percent of potential caucus-goers saying they're completely decided on whom they would support. The GOP candidates are heading into their third debate this Wednesday. 

Patrick Murray, director of the Monmouth University Polling Institute, said in a statement, "Trump's support has eroded in a number of key areas, with the beneficiary being another outside candidate. One question is how secure Carson's new found support really is." 

The poll of 400 potential caucus-goers was taken from Oct. 22-25. It had a margin of error of 4.9 percentage points.