Democratic presidential candidate Bill de Blasio faced bipartisan backlash Thursday after he quoted Marxist revolutionary Che Guevara to pump up a crowd of union members in Miami.

The New York City mayor's detractors included Republican U.S. Sen. Marco Rubio of Florida and Democratic U.S. Rep. Donna Shalala, also of Florida, who served in the Clinton administration.

"It is unacceptable to quote a murderer like Che Guevara," Shalala wrote.

Earlier in the day, de Blasio was captured on video, addressing striking airport workers.

"Hasta la victoria, siempre!" de Blasio shouted. The phrase translates to, "Until victory, always!," and is attributed to Guevara, a key figure in the Cuban Revolution led by Fidel Castro.

"Hasta la victoria, siempre!" — Bill de Blasio, Democrat running for president

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"We will be with you every step of the way," de Blasio added as he spoke to the crowd.

But less than one hour after Miami's WFOR-TV posted a video of his remarks, De Blasio tweeted out an apology, saying he did not mean to offend anyone "who heard it that way." He also claimed he didn't know the phrase was associated with Guevara and offered up a mea culpa for his ignorance.

De Blasio also apologized on camera for his remarks in the debate spin room and said he was only trying to encourage the embattled workers. He said he takes "full responsibility" for his mistake but predicted most voters would move on and not hold it against him.

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"It was an honest mistake. I apologized for it. I understood it just to be a Spanish-language phrase," he said. "I used it not knowing that was the origin. When I heard it was the origin I apologized immediately. Did not mean to offend anybody. I was telling those airport workers -- I thought they were going to win their strike in the end. They responded energetically because it was simply a matter of encouraging them.

"But look, as a leader you have to be able to apologize when you make a mistake. And even though I didn't know the origin I still have to take responsibility and I say I apologize to anyone offended -- didn't get it. I won't -- not make that mistake again for sure."

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But Rubio, a son of Cuban immigrants who has been a vocal critic of the Castro regime and its successors, didn't seem sold on de Blasio's explanation.

Rubio tweeted: "De Blasio studied Latin American politics in college, was a very active supporter of the Sandinistas in #Nicaragua & even honeymooned in #Cuba in violation of U.S. law. But he had NO IDEA he was quoting Che Guevara today. It was all just an incredible coincidence."

De Blasio faced further criticism from Florida's other U.S. senator, Rick Scott.

"In case there was any doubt about the Democrats running for President embracing socialism, @BilldeBlasio is in Miami quoting...Che Guevara," Scott wrote. "You can’t make this up."

Democrats also denounced de Blasio's remark.

Shalala, the Florida congresswoman who previously served as president of the University of Miami and was secretary of Health the Human Services under former President Bill Clinton, called de Blasio's use of a Guevarra quote "unacceptable" and said it was especially ironic for him to use it in Miami.

Annette Taddeo, a Florida state senator from the Miami area, said she was "utterly disgusted" by the Guevara reference.

"This is completely unacceptable! How can anyone wanting to be the leader of the free world quote a murderous guerrilla -in Miami no less! A community filled with his victims!" Taddeo wrote.

After the controversy erupted, many social media users made reference to a 2014 appearance by de Blasio on “The Daily Show” with Jon Stewart, after de Blasio had been elected mayor of New York.

During the interview, they joke about how de Blasio has redecorated City Hall after succeeding billionaire Michael Bloomberg.

“The Che Guevara posters are very popular, they really are,” de Blasio says.

He adds: "I don't wear the Che Guevara T-shirt at work. I have thought about that."

De Blasio also grabbed headlines at Wednesday night's debate among Democratic presidential candidates when he was one of only two candidates who said they'd be willing to sacrifice their own private health insurance in favor of a government plan. The only candidate to join him was Sen. Elizabeth Warren, D-Mass.