US Senator and Democratic presidential candidate Bernie Sanders has overtaken former Vice President Joe Biden in head to head matchup with President Donald Trump, a new poll shows.

The survey, conducted between December 18 and 19 by Ipsos/Reuters, found that 39 percent of US voters favored Sanders over Trump, compared to 37 percent who preferred Biden over the Republican president.

Biden has maintained a steady lead in national polls over other top candidates for several weeks, but primary voters have far from made up their minds.

Recent surveys have determined that Sanders enjoys more support among Hispanic voters and young people between 18 and 29 years old, demographics likely fueling his late-stage surge to the top of the Democratic field.

In the past, Sanders has criticized Biden for his views on domestic issues and foreign policies towards other countries.

Sanders began to eclipse Senator Elizabeth Warren of Massachusetts after the fourth Democratic debate, when multiple candidates attacked Warren on how she would fund her health care plan.

In the Ipsos/Reuters poll, Sanders is supported by more independents (21 percent) and Democrats (74 percent) than both Biden and Warren in matchups against Trump.

Sanders, 78, would become America’s first Jewish president if elected. Nonetheless, he has called on the US government to withhold military aid to Israel if it continues to annex settlements in the occupied West Bank in Palestine.

“I would use the leverage, $3.8 billion is a lot of money, and we cannot give it carte blanche to Israel,” Sanders said in November at the annual convention of J Street, a liberal pro-Israel advocacy group.

“I would say that some of the $3.8 billion should go right now to humanitarian aid in Gaza,” Sanders added, referring to the annual amount of military aid that the United States currently gives to Israel.