NEWARK, N.J. — Republican front-runner Donald Trump is widely unpopular among the nation’s Hispanics, a new AP-GfK poll finds, challenging the billionaire’s assertion that he will win the Hispanic vote if he becomes his party’s nominee.

The survey finds many of the Republican candidates running for president would probably struggle to win significant support among Hispanics in a general election. Jeb Bush and Marco Rubio are their favorites, but even they are a hard sell, the poll suggests.

Even so, most in the field are unknown to enough Hispanics that they might have a shot at proving themselves.

That’s a particular struggle for Trump, who began his campaign by calling some immigrants from Mexico rapists and has vowed to deport all of the estimated 11 million people living in the country illegally if he is elected president. Trump is viewed unfavorably by 72 percent of Hispanics, with 6 in 10 having a very unfavorable opinion of him, the AP-GfK poll finds. Only 11 percent view him favorably.

Among Trump’s rivals, Bush, who speaks fluent Spanish and married a Mexican-born woman, is viewed most favorably by Hispanics, with 26 percent giving the former Florida governor a positive rating. Rubio, a Florida senator and Cuban-American, comes in second, with 23 percent viewing him favorably.

Still, both Bush and Rubio are viewed unfavorably by more than one-third of Hispanics polled.

Trump does have a following of enthusiastic Hispanic backers who have launched groups like “Latinos Support Trump” on social media. During his visit to the Mexican border in the summer, for instance, he was cheered by a dozens of Hispanic supporters, many of whom were born in the country or entered legally and resented those who came against the law.

But advocacy groups say the idea of Trump winning the Hispanic vote is less than unlikely.