DEARBORN, United States (AFP) — United States President Joe Biden scored an easy win in Michigan’s Democratic presidential primary Tuesday but with 50,000 votes from Arab-Americans ticking the “uncommitted” box on the ballot indicating rebuke of the 82-year-old leader over the war in Gaza.

The “Listen to Michigan” campaign was behind the rebuke in a bid to jolt Biden into backing off from his support of Israel in its war against Hamas terrorists.

The significant number of “uncommitted” votes could set off alarm bells ahead of the November general election, when Biden cannot afford to see his coalition eroded in the swing state.

On the Republican side, US news networks projected ex-leader Donald Trump’s victory within seconds of the polls closing, although he has to wait until the weekend for confirmation under a complex system splitting the contest over several voting days.

The former president has swept the early voting states and Michigan was never expected to interrupt his march to the nomination.

His sole remaining challenger, former United Nations ambassador Nikki Haley, lost her home state of South Carolina to Trump over the weekend but has refused to quit, saying she doesn’t believe the former president can defeat Biden.