FORT DODGE, Iowa (Reuters) - U.S. Senator Bernie Sanders and former Vice President Joe Biden appear locked in a tight race for the Democratic presidential nomination, as both campaigned in Iowa on Sunday with only days left until the first contest.

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New polling released on Sunday showed Sanders leading in New Hampshire and tied with Biden in Iowa, the first two states to weigh in the Democratic primary. Gaining momentum at the right time has historically been key to helping a candidate secure the nomination.

A poll of Iowa voters by CBS found Sanders and Biden statistically tied, with 26% and 25% respectively. Pete Buttigieg, the former mayor of South Bend, Indiana, was within striking distance at 22%.

Biden led with 25% in separate poll of Iowa voters by Suffolk University/USA TODAY Network Poll released on Sunday evening. Sanders registered second at 19%, followed by Buttigieg at 18%.

Sanders led a poll released on Sunday of New Hampshire voters with 25% support. His closest competitor was Biden, with 16%, according to a poll by cable network CNN and the University of New Hampshire.

A national Washington Post-ABC poll released on Sunday found Biden in the lead with 32% support, followed by Sanders at 23%. U.S. Senator Elizabeth Warren received 12%, and former New York City Mayor Michael Bloomberg was at 8%.

Sanders’ recent rise in polling appears to be the product of consolidating the liberal wing of the party. Biden has remained at the top of the pack, but appears to be struggling to consolidate the more-centerist wing of his party.

Biden is making the pitch that he is more likely to beat Republican President Donald Trump in the November 2020 election.

Kelly Walsh, 53, a nurse in Marshalltown, Iowa, attended a Sanders rally on Saturday, with her two teenage sons. She likes both Biden and Sanders.

“I want somebody that can definitely beat Trump so I kind of like Joe Biden,” she said, drawing a disapproving look from her 15-year-old, Hayden.

She agrees with most of Sanders’ platform, especially his government-run healthcare plan, but worries it would put off moderates.

“If I knew Bernie could do it and he didn’t scare everybody else, I’d be 100%,” she said.

U.S. Representative Cindy Axne, who represents a district in Iowa and endorsed Biden, said she does not want Iowa to help nominate a candidate who cannot beat Trump.

“We don’t want to make a bad decision,” she told Reuters at an event for Biden.

Candidates struggling to still build traction are facing crunch time. U.S. Senator Amy Klobuchar, who is still trying to break 10% in polls, picked up the endorsement of the New Hampshire Union Leader newspaper. The largest publication in the state, the historically conservative editorial page has previously had more influence in Republican primaries.