MILWAUKEE — Ted Cruz swept to victory in the Wisconsin primary Tuesday, complicating Donald Trump's bid to win the necessary number of Republican delegates to head off an open convention this summer.

"Tonight is a turning point," Cruz told supporters in Milwaukee. "It is a rallying cry ... We have a choice, a real choice."

While Cruz proclaimed a reset of the Republican race, the Trump campaign said it would rally in future states and attacked the Texas senator as a proxy for a Republican establishment that wants to "steal" the nomination from the New York businessman.

Cruz, as he did throughout a two-week campaign, said other states will follow Wisconsin's lead and eventually give him enough delegates to win the nomination either before or during the Republican convention that starts July 18 in Cleveland.

"Together we will win a majority of the delegates," Cruz told a crowed jammed into a small hall at the American Serb Hall Banquet. "And together, we will beat (Democrat) Hillary Clinton in November."

Trump, who had acknowledged the possibility of defeat in the Badger State, said earlier in the day he was already looking forward to primaries in his home base of New York and other northeastern states in the weeks ahead. Both Cruz and Trump are scheduled to campaign Wednesday in New York, which hosts a primary on April 19.

In a post-primary statement, Trump's campaign said its candidate had to fight not just Cruz, but anti-Trump campaign organizations, critical radio talk-show hosts in Wisconsin, and the Republican Party establishment in general.

"Ted Cruz is more than a puppet," the statement said. "He is a Trojan horse, being used by the party bosses attempting to steal the nomination from Mr. Trump."

At his watch party at the Serb Hall in Milwaukee, Cruz told backers they are "uniting the Republican Party" behind his candidacy and against Trump.

As the crowed chanted "Cruz! Cruz! Cruz!" the candidate closed with "Hillary, get ready — here we come!"

Cruz, Trump and Ohio Gov. John Kasich sought 42 Republican convention delegates available in Wisconsin, with precise allocations yet to be determined Tuesday night.

Various anti-Trump organizations also spent money in Wisconsin, seeing it as an opportunity to blunt the businessman's momentum and make it harder for him to amass the 1,237 delegates he will need to claim the GOP presidential nomination.

Trump led the GOP race with 737 delegates as of Tuesday, according to the Associated Press, less than half the total won. Cruz had 481 delegates and Kasich had 143, while Marco Rubio — who dropped out of the race last month — remains credited with 171 delegates. 

Sen. Lindsey Graham R-S.C., a former foe who recently endorsed Cruz, tweeted "well done" to the Texas senator as the Wisconsin results rolled in, adding that "hopefully tonight is the turning point to deny" Trump the delegates he needs for nomination.

Kasich stayed off the campaign trail Tuesday. Though both Trump and Cruz have called on Kasich to exit the race, saying he has no chance to win the nomination, the Ohio governor says that none of the candidates will have a majority of delegates when the convention begins in Cleveland.

"There is going to be an open convention, and it's going to be cool," Kasich said this week on Fox News.

Kasich chief strategist John Weaver issued a memo Tuesday proclaiming the race "wide open," and adding that this will be remembered as the week in which both Cruz and Trump "both effectively admitted they will not reach the GOP convention with enough bound delegates to be the nominee."

Trump came into the Wisconsin primary after one of the worst stretches of his campaign. The New York businessman took criticism from members of both parties for comments suggesting that women should be punished for abortions — a position he then reversed — and that the United States should pull back from military commitments to NATO and Asian allies such as Japan and South Korea.

A number of radio talk-show hosts in Wisconsin also spoke out against Trump during the primary.

Cruz jumped on Trump's mistakes, saying he would be a "train wreck" nominee in the fall who could cost the Republicans control of the Senate and House.

Trump said  "Lyin' Ted" Cruz would lead the GOP to defeat in the fall.

The Republican front-runner began primary day in Wisconsin with an addendum to a long-standing proposal: building an anti-migration wall along the U.S.-Mexican border, to be financed by the Mexican government itself. Trump proposed to do that by pressuring Mexico via the denial of "remittances," money that migrants in the USA send back to family members in their home countries.

"This provides substantial leverage for the United States to obtain from Mexico the funds necessary to pay for a border wall," Trump said.

Critics questioned the practicality and legality of Trump's proposal.

"The notion that we're going to track every Western Union bit of money that's being sent to Mexico?" President Obama said at the White House. "Good luck with that."

In the wake of Wisconsin, Trump and supporters said he has a number of politically hospitable states on the  primary schedule, starting with the April 19 contest in New York. A week later, five more Northeast states pick delegates: Pennsylvania, Connecticut, Delaware, Maryland and Rhode Island.

Cruz said polls in future states will shift his way in the wake of Wisconsin.

"Tonight," he told supporters, "Wisconsin has lit a candle guiding the way forward."