MILWAUKEE – Republican Ted Cruz has defeated front-runner Donald Trump in the Wisconsin presidential primary today, dealing at least a temporary setback for the New York billionaire hoping to amass the delegates needed for the party’s nomination ahead of the July convention.

Multiple US networks called the race early in the Midwestern state that borders Canada. With seven percent of precincts reporting, Cruz was ahead with 49 percent of the vote compared to Trump’s 35 percent.

Cruz’s win was a breakthrough for Republican Party forces battling to block Trump, and it raised the prospect of a prolonged nominating fight that could last to the July convention.

Democratic presidential contender Bernie Sanders also won in Wisconsin, gaining momentum in his fight against front-runner Hillary Clinton and trimming her commanding lead in delegates.

Trump had 737 convention delegates to Cruz’s 481 heading into the vote, leaving him 500 delegates short of the 1,237 needed to become the party’s nominee in the November 8 election. Cruz and Ohio Governor John Kasich, the other remaining Republican contender, hope to stop Trump short of a first-ballot victory and trigger a contested convention.

Cruz, a conservative US senator from Texas, was aided in Wisconsin by the backing of Republican Governor Scott Walker, who had dropped his own presidential bid in September. Party establishment figures, worried that Trump will lead Republicans to a broad defeat in November, have banded together to try to stop him.

The Wisconsin primary followed a difficult week for Trump, who was forced to backtrack after saying women who have abortions should face punishment if the procedure is outlawed, and who voiced support for his campaign manager after he was charged with misdemeanour assault for grabbing a reporter.

– with other agencies