Democratic presidential contenders Bernie Sanders and Pete Buttigieg, the top finishers in Iowa’s first nominating contest, faced a barrage of criticism on Friday from rivals who said they did not have what it takes to beat Republican Donald Trump in November.

In a heated debate in New Hampshire just four days before the state’s pivotal primary, their Democratic rivals questioned whether Sanders’ democratic socialist views and Buttigieg’s relative lack of experience and lack of support with African-Americans and Latinos made them too much of a risk for the Nov. 3 election.

Sanders, 78, a U.S. senator and leader of the party’s progressive wing, and Buttigieg, the 38-year-old former mayor of South Bend, Indiana, finished in a virtual dead heat in Iowa’s first-in-the-nation caucuses earlier this week.

Former Vice President Joe Biden, the one-time national front-runner who finished a disappointing fourth in Iowa, delivered his most aggressive performance yet, a sign of possible desperation as he looks to rebound.

Biden said Trump would have an easy time ripping into Sanders in a general election campaign, and Sanders would drag down other Democratic candidates in federal and state races.

“Bernie has labeled himself, not me, a democratic socialist. I think that’s the label that the president is going to lay on everyone running with Bernie if he is the nominee,” Biden said.

U.S. Senator Amy Klobuchar, who finished a distant fifth in Iowa, said Sanders would not attract the kind of centrist voters Democrats need to win.

“Donald Trump’s worst nightmare is a candidate who will bring people in from the middle,” Klobuchar said at the eighth Democratic debate. “I think we need someone to head up this ticket that actually brings people with her instead of shutting them out.”

Sanders, who has called for a political revolution that will attract new voters, said “the way to beat Trump is by having the largest voter turnout in the history of this country.” He said he could appeal to working class voters who have given up on the political process.

Biden and Klobuchar also questioned whether Buttigieg had enough experience to face off with Trump.

Buttigieg, who served two terms as mayor of South Bend, a city with a population of 100,000, said the Washington insider experience of some of his rivals was no longer what was needed, and it was time to “turn the page” on the old Washington politics.

“It is easy to go after Washington, because that’s a popular thing to do,” Klobuchar said, telling Buttigieg that “it’s popular to say and makes you look like a cool newcomer.”

Reuters/AP