Republican presidential candidate Ted Cruz (R-TX) speaks at the California GOP convention in Burlingame, California, U.S., April 30, 2016. Reuters

U.S. presidential candidate Ted Cruz made a plea to the California Republican Party on Saturday to line up behind him in the state's June primary in his uphill battle to stop front-runner Donald Trump from grabbing the nomination.

At the same party convention that was the backdrop for chaotic protests against Trump Friday, Cruz tried to woo party members with support for their longtime issues, such as lower taxes and a harder line on immigration.

Former California Gov. Pete Wilson gave Cruz his endorsement as he introduced the senator from Texas.

Cruz received more applause at the convention than either Trump or third-place candidate Ohio Gov. John Kasich, who also spoke Friday.

"If we're fractured and we're divided, Hillary Clinton wins, and the campaign is lost," he said, referring to the Democratic Party's front-runner in the Nov. 8 election for the White House.

Now mathematically eliminated from securing the nomination on the first ballot at the party's convention in Cleveland in July, Cruz aims to stop Trump from receiving the 1,237 delegates needed to win the nomination outright, forcing a contested convention.

However, the prospect of him being able to do so has grown increasingly slim.

Ted Cruz Presidential Candidate Profile | InsideGov

Trump, a billionaire businessman and former reality TV star, has continued to notch up wins in the nation's nominating contests, including a five-state sweep of the latest string of contests last Tuesday.

Cruz has downplayed the severity of the losses and in his speech Saturday looked forward to upcoming contests, which he has said will put him on the path to thwarting Trump.

"California is going to decide this Republican primary," he said, referring to the state's June 7 contest.

Trump has been at odds with the party's establishment and has called the system for nominating its candidate "rigged."

Critics say he has played on the fears of his supporters, especially about immigration, by proposing a temporary ban on Muslims entering the country and accusing illegal Mexican immigrants of being rapists and criminals.

On Thursday and Friday, anti-Trump protests erupted outside the candidate's California events. On Friday, he was forced to halt his motorcade and go through a back entrance to a hotel to give a speech to the convention and avoid several hundred loud protesters gathered outside.

Cruz hopes to slow Trump's march toward the nomination in Indiana's primary on Tuesday. The state awards its 57 delegates on a winner-take-all basis by congressional district, possibly granting Cruz a windfall of pledged delegates.

A Real Clear Politics polling aggregation in the state shows Cruz just behind Trump, 35.2 percent to 37.5 percent.

Polls show Cruz has more of a challenge in delegate-rich California, where he lags Trump 28.3 percent to 45.7 percent.

In an indication of efforts to court the state, Cruz on Wednesday made the unusual move of naming a vice presidential running mate, onetime presidential hopeful Carly Fiorina, who was formerly a chief executive of the California technology company Hewlett-Packard Co.

On Saturday night, she urged the crowd of party faithful, many of whom had backed her as the party's nominee in a failed bid for U.S. senate in 2010, to join her in supporting Cruz.

In a dynamic and combative speech, she urged Kasich to get out of the race and challenged the idea that Trump had locked up the nomination.

"Donald Trump was here yesterday, and he was telling you it's over," Fiorina said. "But the 30-yard line ain't a touchdown."