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Kamala Harris leads among likely voters in Iowa, a state that Donald Trump won by more than eight points four years ago. That's according to a closely watched poll that suggests female voters in the Midwest could fuel a late surge in support for the Democratic vice president.

A Des Moines Register/Mediacom Iowa poll late Saturday showed Harris leading Trump in the Midwest state 47 percent to 44 percent just days before the election.

Iowa, where the caucuses that begin the presidential nominating process are held, was long considered a battleground state but has trended increasingly Republican in recent years. Trump defeated Joe Biden there by more than eight points in 2020, and the nonpartisan Cook Political Report rated the state as “solid Republican” in this year's presidential race.

But the surprising new poll will almost certainly set off alarm bells for Trump's campaign. Harris has largely focused her efforts in the final stretch of the campaign on winning the so-called “Blue Wall” of neighboring Wisconsin, Michigan and Pennsylvania.

The Des Moines Register poll was conducted by veteran, nonpartisan pollster J Ann Selzer, whose poll has long been considered the “gold standard” of Iowa polling by both Democratic and Republican political activists.

“No one can say they saw this coming,” Selzer told the newspaper. “(Harris) has clearly taken a leadership position.”

The Iowa poll suggests that Harris' surge can be partly explained by increasing support among independent women voters. The poll found Harris had a 13-point lead among all independents and a 28-point lead among independent women in the state, with 57 percent supporting Harris and 29 percent supporting Trump.

Harris – who would be the first female US president if elected – made explicit overtures to female voters in the final stretch of her campaign. She emphasized her support for abortion access and reproductive rights and blamed Trump for overturning the Roe v. Wade ruling, which enshrined the nation's right to abortion.

Iowa is one of more than a dozen Republican-controlled states that now ban almost all abortions after six weeks of pregnancy, before many women realize they are pregnant.

National opinion polls have consistently shown a gender divide in the electorate, with women broadly saying they are more likely to support Harris and men more likely to vote for Trump.

Still, the Iowa poll remains an outlier. The Financial Times poll tracker shows Harris with a razor-thin lead of around one point over Trump in national polls.

Meanwhile, the two candidates remain statistically tied in the seven swing states – the “blue wall” states plus North Carolina, Georgia, Nevada and Arizona – which analysts and campaigns say will likely determine who wins the White House.