Washington, Feb 28 (IANS): Voters went to the polls across Michigan, a battleground state, for the 2024 US presidential primary.

In the Republican race, former US President Donald Trump, who remains undefeated so far this year, continues to be challenged by former US Ambassador to the United Nations and former South Carolina Governor Nikki Haley, Xinhua news agency reported.

Tuesday's GOP primary will determine only a portion of how Michigan's delegates will be awarded while the rest will be decided at a state party convention scheduled for Saturday. Trump has a clear lead over Haley in Michigan polls.

US President Joe Biden does not have a major challenger in the Democratic primary, with Minnesota Congressman Dean Phillips polling only in single digits nationally, but some activists are urging Michigan Democrats to vote "uncommitted" in protest of the Biden administration's response to the conflict in Gaza.

The economy is the top issue for 31 per cent of Michigan voters, followed by immigration, threats to democracy, healthcare, housing affordability, education, crime and abortion access, according to a new Emerson College Polling/The Hill survey.

Trump narrowly flipped Michigan, also a Rust Belt state, in the 2016 presidential election, defeating Hillary Clinton by just 0.2 per cent. Four years later, Biden won by 2.8 per cent, bringing it back to the Democratic column.

The US presidential primaries, extending through June, precede the Republican National Convention in July, where the party's presidential nominee is officially selected by delegates, followed by the Democratic National Convention in August, leading up to the 2024 Election Day on November 5.