Milwaukee (US), Apr 6 (IANS): Senator Ted Cruz has won the Republican presidential primary in Wisconsin, dealing a blow to front-runner Donald Trump, while Democratic contender Senator Bernie Sanders defeated Hillary Clinton in a close contest.

The loss is more damaging to Trump, because he is in greater danger of failing to lock up the party's nomination ahead of the July convention.

In the Republican race, the first results showed a massive lead for Cruz: With more than 20 percent of votes in, he led Trump by more than 20 percentage points. Trump may still get some delegates from Wisconsin, however, the state awards some delegates by congressional districts, and Trump was leading in rural districts in Wisconsin's northwest, according to Washington Post.

Cruz savoured the victory, casting it as proof that the GOP race had turned. The party's anti-Trump forces had coalesced behind an unlikely champion: a Texas senator who seemed like the worst possible choice for the GOP establishment, right up until they met candidate Trump.

"Tonight is a turning point. It is a rallying cry," Cruz told supporters in Milwaukee. "We have a choice. A real choice. The national political terrain began to change two weeks ago," he said, meaning when he won by a large margin in Utah. Cruz said his campaign had raised $2 million on Tuesday alone.

In the Democratic race, Sanders was leading Clinton by about seven percentage points, 53 percent to 46 percent, with 30 percent of precincts reporting

A victory on that scale may not allow him to make up significant ground on Clinton in the race for Democratic convention delegates. But it will allow Sanders to cite growing momentum going into a crucial contest in New York, where Sanders was born - and where Clinton served as senator - on April 19.

A win in Wisconsin also allows Sanders to make the case to "super-delegates", who can make up their minds about whom to support.