By Emily Flitter and Daniel Trotta
NEW YORK (Reuters) - Republican front-runner Donald Trump on Thursday talked up "New York values" and urged his home state voters to give him a big win next week, but his rivals warned nominating Trump could lead to disastrous losses to the Democrats in the Nov. 8 election.
The New York billionaire is in danger of being forced to try to capture the Republican presidential nomination through a contested convention because opposition from rivals Ted Cruz and John Kasich is chipping away at his lead.
As protesters chanted outside and waved signs against Trump, Trump told the New York state Republican Party's gala that he needs the momentum that a victory in the state's primary would bring next Tuesday.
"New York is so important," Trump said, trying to regain the momentum he lost after Cruz defeated him in Wisconsin last week and captured all of Colorado's delegates.
Trump identified himself with "New York values" of hard work and compassion after Cruz charged Trump's version of these values are basically Democratic positions.
Whether Trump can win the 1,237 delegates he needs for the nomination is an open question as both Cruz, a U.S. senator from Texas, and Ohio Governor Kasich, try to block him from getting enough delegates. They want to extend the fight to a contested convention in Cleveland when Republicans gather to formally choose their nominee in July.
In his speech to the group, Kasich tried to raise questions about Trump without mentioning his name. He said Republican candidates across the country would be at risk with a candidate with a negative message at the top of the ballot.
Trump has drawn many protests for policy positions that include building a wall along the U.S. border with Mexico, deporting 11 million illegal immigrants and banning Muslims temporarily from entering the United States.
"We risk losing everything from the White House to the courthouse to the state house if we don't advance a positive, uplifting, unifying message to this country. That is what we need to do," said Kasich, who spoke after Trump.
Cruz, speaking after Kasich, continued the theme, pointing to polls showing Trump losing badly to Democratic front-runner Hillary Clinton and getting far less support from women and minority voters.
Cruz presented himself as a unity candidate who can bring the various wings of the party together.
"If we nominate a candidate who loses to Hillary Clinton by double digits, who loses to women by 20 points, who loses Hispanics by 40 points, who loses young people, we cannot win in the general (election)," said Cruz.
Before the event started in the Grand Hyatt hotel near Grand Central Station, a group of protesters stormed the hotel mezzanine with a banner that read: “NYC Rejects the Party of Hate.” Eleven of them were reported arrested.
Outside the hotel, many anti-Trump demonstrators called the New York billionaire businessman a fascist or white supremacist. They even teased him about his signature hairdo.
"We Shall Over Comb," read one sign. Others said: "Deport Trump," "No allegiance for Trump," and "Black lives matter."
A series of speakers addressed the protest crowd with a loudspeaker. Police set up portable barriers to keep protesters separated from traffic and allow pedestrians to pass on busy 42nd Street.
"Although Trump is from here, there is no place for him here," said one of the speakers, Nabil Hassein, 27, of the group Millions March NYC.
Kasich scored a victory with the endorsement of former New York Governor George Pataki, an unsuccessful candidate for the Republican nomination for the Nov. 8 election.The Trump campaign got some good news when a Florida prosecutor announced that Trump's campaign manager, Corey Lewandowski, would not be prosecuted on a misdemeanor battery charge involving a reporter he was accused of grabbing at an event last month.
(Additional reporting by Susan Cornwell in Washington; Writing by Steve Holland; Editing by Jonathan Oatis and Peter Cooney)