Tough crowd. (AP Photo/J. Scott Applewhite, File)

MIAMI -- Sen. Marco Rubio (R-Fla.) was loudly heckled by critics of his position on immigration reform on Friday night during a speech here to promote his new book.

Rubio spoke before several hundred people packed into an auditorium at the downtown campus of Miami Dade College, one of several stops on a nationwide tour to promote his book, "American Dreams," his broadly written treatise on economic policy.

At least eight young people interrupted Rubio just as he began speaking about how the United States is a country of freedom and opportunity.

"What about my parents?" shouted one of the protesters, prompting others to join in.

As they began shouting, Rubio told the hometown crowd that he's among a few national political figures to be regularly heckled "by both sides of the immigration debate."

"I just hope you bought the book," Rubio quipped as campus security officers grabbed and pulled out a few of the protesters.

"If what they wanted was a discount of the book we could have worked it out," he added later.

"Get out of here!" some of the senator's supporters shouted as security officers struggled to quickly removed the protesters.

Rubio also apologized after one of the hecklers shouted at him using an expletive.

The senator faced similar face-to-face criticism or questioning by critics of his immigration policy during stops in Des Moines and Las Vegas, according to aides.

Rubio was part of a bipartisan "Gang of Eight" that wrote a comprehensive immigration reform bill that was passed by the U.S. Senate in 2013. The bill faltered in the GOP-controlled House and Rubio has suffered criticism ever since from conservatives who fault him for working with Democrats to pass legislation they consider too friendly to the nation's millions of undocumented immigrants. As the bill's prospects declined in 2013, Rubio distanced himself from the work, suggesting that Congress would need to pursue a piecemeal approach to the complex issues surrounding immigration and border security.

As he ponders running for president, Rubio also faces reelection to his Senate seat in 2016 and the seat is a big target for Democrats eager to pick up congressional seats during a presidential election cycle.

In his remarks, Rubio discussed several of his economic proposals designed to help lower-income Americans climb out of poverty. Among his ideas is a proposal to allow what he called "private sector investors" to help pay the student loan debt of graduate students. In return, the investor would reap a percentage of the student's income once they earned a job.

He later signed copies of the book for supporters who waited in a long line in the auditorium for a few brief moments to greet him.

Rubio's next stop is Monday and Tuesday in New Hampshire, where he'll hold another book event and speak at the state's heralded "Politics and Eggs" breakfast.

Before the event, Rubio fielded questions from a large pack of local and out-of-town reporters, including a French television crew.

The Florida senator dismissed reports that he's being pressured by the National Republican Senatorial Committee and other GOP leaders to opt out of a presidential campaign and run for reelection instead.

"That may be how they feel, but in terms of pressure and so forth, it's just not accurate. I don't think I've had a single member of the Senate pressure me to do anything," he said.

But he added that the Florida GOP "has a deep bench" of political talent poised to run for office at all levels, if needed.

This story has been updated.