By Curtis Skinner and Valerie Vande Panne

(Reuters) - Students held rallies on college campuses across the United States on Thursday to protest ballooning student loan debt for higher education and rally for tuition-free public colleges and a minimum wage hike for campus workers.

The demonstrations, dubbed the Million Student March, were planned just two days after thousands of fast-food workers took to the streets in a nationwide day of action pushing for a $15-an-hour minimum wage and union rights for the industry.

About 50 students from Boston-area colleges gathered at Northeastern University carrying signs that read "Degrees not receipts" and "Is this a school or a corporation?"

"The student debt crisis is awful. Change starts when people demand it in the street. Not in the White House," said Elan Axelbank, 20, a third year student at Northeastern, who said he was a co-founder of the national action.

Photos and videos posted on social media showed marches at schools including Texas State, the University of Massachusetts at Amherst and Depaul University in Chicago.

Organizers are demanding tuition-free public colleges, cancellation of all student debt and a $15-an-hour minimum wage for campus workers.

The total volume of outstanding U.S. student loan debt has more than doubled to $1.2 trillion, according to the U.S. Consumer Financial Protection Bureau, compared with less than $600 billion in 2006.

Saddled with debt that can sometimes run into hundreds of thousands of dollars, many college graduates struggle to make payments amid an ailing economy and job market.

"I want to graduate without debt," said Ashley Allison, a 22-year-old student at Boston's Bunker Hill Community College, at the Northeastern rally. "Community college has been kind to me, but if I want to go on, I have to take on debt."

Dealing with swiftly mounting student loan debt has been a focus of candidates vying for the White House in 2016.

Democratic hopeful Bernie Sanders has vowed to make tuition free at public universities and colleges, and has pledged to cut interest rates for student loans.

Story continues

His rival Hillary Clinton has said she would increase access to tuition grants, let graduates refinance loans at lower interest rates, and streamline income-based repayment plans.

Florida U.S. Senator Marco Rubio, the most prominent Republican candidate to lay out a concrete proposal, says he would establish an income-based repayment system for federal student loans and would simplify applications for federal aid.

(Reporting by Curtis Skinner in San Francisco and Valerie Vande Panne in Boston; Editing by Lisa Shumaker and James Dalgleish)