DES MOINES, Iowa -- With the Iowa caucuses kicking off the presidential nominating calendar in just four days, White House hopeful Pete Buttigieg turned up the volume on Thursday as he targeted by name two of his top rivals for the Democratic nomination.

In some of his most cutting comments to date, the former South Bend, Ind., mayor took aim during a campaign event in Decorah, Iowa, at progressive Sen. Bernie Sanders of Vermont, saying “I hear Senator Sanders calling for a kind of politics that says you've got to go all the way here and nothing else counts."

Fox News’ Andres del Aguila reports that Buttigieg then emphasized that “it's coming at the very moment when we actually have a historic majority, not just aligned around what it is we're against, but agreeing on what it is we're for."

The 38-year-old candidate – the youngest in the still-large field of Democratic presidential contenders – also took aim at former Vice President Joe Biden – who along with Sanders is a co-front-runner in the latest polling in Iowa’s Democratic caucuses.

"I hear Vice President Biden saying that this is no time to take a risk on someone new," Buttigieg told the crowd. "But history has shown us that the biggest risk we could take with a very important election coming up is to look to the same Washington playbook and recycle the same arguments and expect that to work against a president like Donald Trump who is new in kind."

Buttigieg’s blast at Biden followed a similar jab at a Fox News town hall on Sunday, when the candidate took an indirect jab at the former vice president.

"I've heard some folks saying this is no time to take a risk," Buttigieg emphasized at the town hall. "And I agree. But I think the biggest risk that we could take right now would be to try to go up against this president with the same old playbook that we've been relying on that helps explain how we got here in the first place. I think it's time for something completely different."

Biden -- speaking with reporters including Fox News’ Allie Raffa later in the day during a stop at a Dairy Queen in Pella -- said that Buttigieg’s “a good guy. ... He must be deciding things are getting a little tight.”

A strong finish in Iowa is crucial to Buttigieg’s chances of winning the Democratic presidential nomination. The latest poll, a Monmouth University survey released on Wednesday, has Buttigieg at 16 percent support among likely Democratic caucuses goers in Iowa. That has him trailing Biden, who is at 23 percent, and Sanders, who is at 21 percent. Sen. Elizabeth Warren of Massachusetts is at 1 percentage point behind Buttigieg.

Biden: ‘Bernie has a different view’

While taking orders at the Dairy Queen in Pella, Iowa, Biden also took aim at Sanders, the longtime independent populist lawmaker who’s making his second straight run for the Democratic nomination.

Asked about the differences between himself and Sanders, the former vice president laughed and said “I’m a Democrat.”

“He says he’s not. He says he’s not a registered Democrat and Bernie has a different view,” Biden added.

Biden unleashes on Trump in final Iowa blitz

Hours before President Trump was scheduled to arrive in Iowa to hold a large rally ahead of Monday’s caucuses, Biden launched a full frontal attack on the Republican incumbent over Trump’s “culture of cruelty” during a speech in suburban Des Moines.

“This is a president who laughs at, insults, demeans and demonizes other people,” the former vice president emphasized Thursday as he spoke to 275 people in Waukee, Iowa, in a speech that was touted by his campaign as a pre-buttal to Trump’s rally hours later.

“He’s more a bully than a president,” Biden spotlighted as he jabbed at the president in what could be a preview of the pending general election.

“Welcome to Donald Trump’s world. Up is down. Lies are the truth. Allies are enemies. Everything is through the looking glass,” Biden emphasized.

Pence: 2020 Dems are ‘so far left’

Vice President Mike Pence, Biden’s successor as vice president, criticized the Democratic White House field as he kicked off a full day of campaigning in Iowa.

Fox News' Matt Leach noted that Pence -- speaking in Sioux City, Iowa, on Thursday -- referenced the Democratic presidential debate in Iowa earlier this month and said that “those candidates were so far left” that he thought that the stage would tip over.

And pointing to Sanders, who’s at the top of some of the most recent polls in the Hawkeye State, the vice president said that the “leading candidate in Iowa is a socialist.”

Sanders has long described himself as a Democratic Socialist.

Pence was scheduled to cap his day by teaming up with the president at a large rally at Drake University in Des Moines.

Trump supporters gathered at Drake University earlier in the day, waiting to get inside the venue.

Scott Whiton of Perry, Iowa, told Fox News “I support the man and what he’s doing. ... He’s fighting for us and that’s big.”

Whiton was optimistic the president would win re-election and pointed to the ongoing Senate impeachment trial of Trump.

“I think the Democrats are shooting themselves in the foot with all this impeachment crap going on,” he emphasized.