Joe Biden won the Democratic primary race in Michigan but faced a significant protest vote from Americans who oppose his stance on the war in Gaza, early results suggest.

The first ballots counted on Tuesday night suggested the President had won around 79 per cent of the vote, while around 16 per cent chose to mark themselves as “uncommitted”.

In previous contests, around 20,000 voters in Michigan said they were not attached to any prospective nominee, but results suggest the figure in this year’s primary is likely to be far higher.

Incumbent presidents running for re-election can normally expect almost total support from their party.

However, Mr Biden has faced significant opposition in Michigan, which has a large Muslim population, over his handling of the war in Gaza – raising concerns over the strength of his presidential campaign ahead of November’s election.

The primary contest also saw Donald Trump take an easy victory over Nikki Haley in the Republican primary, continuing his undefeated run in this year’s race.

The result was called by US news outlets moments after polls closed at 9pm local time (2am GMT) on Tuesday night.

Listen to Michigan, a campaign group backed by the Palestinian-American Democrat congresswoman Rashida Tlaib, urged progressive voters in the state to mark themselves as uncommitted, rather than support Mr Biden.

“I was proud today to walk in and pull a Democratic ballot and vote uncommitted,” Ms Tlaib said earlier on Tuesday.

“We must protect our democracy, we must make sure that our government is about us, about the people.

“When 74 per cent of Democrats in Michigan support a ceasefire yet President Biden is not hearing us, this is the way we can use our democracy to say ‘listen’.”

Karine Jean-Pierre, Mr Biden’s press secretary, said on Tuesday that the president “cares about what that community is feeling very deeply.”

“We believe it’s important that they feel that they are able to to express themselves and voice their feelings and their concerns,” she said.

A collapse in support among Arab-Americans and young liberal voters over Gaza has concerned Democrat strategists, who believe it could harm Mr Biden in November’s presidential race.

Michigan, which has one of the highest state Muslim populations in the US, is also a key battleground for Mr Biden that he won by a margin of less than three percentage points in 2020.

In the Republican primary, early results suggested Mr Trump had won around 65 per cent of the vote, to Ms Haley’s 31 per cent.

Ms Haley’s defeat in Michigan – which was predicted by opinion polls – comes as she struggles to maintain credibility in the Republican primary race.

Another crushing defeat for Haley

The former UN ambassador has lost every state vote so far to Mr Trump, including her home state of South Carolina on Saturday.

Despite heavy losses of up to 20 percentage points and the decision of other Trump rivals to suspend their campaigns, Ms Haley has pledged to stay in the contest to give Republican voters an “alternative”.

“They have the right to a real choice, not a Soviet-style election with only one candidate,” she said on Saturday, adding: “I have a duty to give them that choice.”

The Michigan result comes ahead of Super Tuesday on March 5, the most significant date in the primary calendar, when voters in 16 states will vote for their preferred presidential nominee on the same day.

It is expected to deliver another series of blows to Ms Haley’s campaign. 

Bookmakers have given her shot at the nomination an implied probability of less than 7 per cent, while national polls show that more than three quarters of Republican voters support Mr Trump.

Primary contests in Michigan are open, allowing all voters to cast a ballot in either the Republican or Democratic race.

Ms Haley’s campaign has attempted to capitalise on “open” races, hoping to attract Democrats or non-affiliated voters to support her and defeat Mr Trump.

However, she has lost all primaries in open states that have voted so far, including South Carolina and New Hampshire.

Olivia Perez-Cubas, Ms Haley’s campaign spokesman, attempted to frame the Michigan result as a weak performance for Mr Trump.

She said: “Donald Trump is losing about 35 per cent of the vote. That’s a flashing warning sign for Trump in November. Since Trump became president in 2016, he lost Michigan Republicans the state House, state Senate, and Governor’s mansion.

“What was once a beacon for the conservative cause, the Michigan Republican Party is now fractured and divided.

“Let this serve as another warning sign that what has happened in Michigan will continue to play out across the country. So long as Donald Trump is at the top of the ticket, Republicans will keep losing to the socialist Left. Our children deserve better.”

Mr Trump has pivoted his campaign to attacks on Mr Biden, kicking off his general election campaign early on the assumption that he will become the Republican nominee at this year’s convention in July.

His team believes he will have the required number of Republican delegates to effectively end the contest by March 12 – less than two months after the primaries began in Iowa in January.