BERKELEY (KTVU) -- Donald Trump set social media on fire Thursday -- the same day that Cinco de Mayo was celebrated -- with a controversial post that raised new questions about the presumptive Republican presidential nominee's true feelings about the nation's Latinos.
The photo on Donald Trump's Twitter account showed Trump eating a taco bowl with the caption "Happy #CincoDeMayo! The best taco bowls are made in Trump Tower Grill. I love Hispanics!"
In San Francisco's Mission District, some people noted that Trump's comment directly contradicts earlier statements he has made about Mexicans.
"I'm surprised because at the beginning he was talking negatively about Hispanics," said Maricella Nunez of San Francisco.
Last summer, Trump came under fire after he described Mexican immigrants as "criminals" in a June 16, 2015 speech.
"They're bringing drugs. They're bringing crime. They're rapists," he said at the time. "And some, I assume, are good people."
UC Berkeley Professor of Political Science Chris Zepeda-Millan says Trump poses a big problem for the Republican Party's efforts to attract Latino voters.
"Mexicans are the largest of the entire Latino population, so when we talk about the importance of the Latino vote, the reason that immigration is such a big issue and continues to poll at the top of issues for Latinos it's because it's such an important issue for Mexicans and Central Americans," Zepeda-Millan said.
"Historically, about one-third of Latinos have voted Republican," he added. "Donald Trump is polling with an 80 percent unfavorable rate. This is unprecedented for a Republican candidate and a lot of it has to do with his rhetoric."
Zepeda-Millan says data shows that more Latinos likely will register and turn out to vote this year, and Trump's rhetoric could hurt him in swing states such as Florida, Colorado, Nevada and New Mexico, where the Latino population has expanded.
"You're going to see in this presidential election what I'm calling the Latino "Trump bump," Zepeda-Millan said, "Recent polling has shown that the number one issue motivating Latinos to get out and vote in this presidential election is to vote against Trump."
Latino voters are not a monolithic group and represent many different races, ethnicities, cultures, and national backgrounds. Zepeda-Millan says that while previous social movements were regional, such as Cesar Chavez and the farmworkers movement in the West, or the Young Lords in the East, there is a broader nationwide movement that is beginning to coalesce.
"For the first time in Americans history you see this national Latino social movement occurring and it's all in response to this anti-immigrant, anti-Latino rhetoric," Zepeda-Millan said.
However, there are Republican Latinos who support Trump.
"Mr. Trump employs thousands of Hispanics, hundreds of thousands are voting for him and millions will and they support him," said Leo Lacayo, a Trump supporter and chairman of the San Francisco Hispanic Republicans.
Democrats are also under fire from some Latino voters who disapprove of the deportations by President Obama's administration.
Both parties will face increasing pressure to win over Latino voters this election year, if they hope to win the White House in November.
KTVU reporter Jana Katsuyama contributed to this report.