* Urges Congress to extend low interest rates for students
* Romney agrees on need to hold down student loan rates
* More than 7.4 million college students could be affected
By Jeff Mason
CHAPEL HILL, N.C., April 24 (Reuters) - Describing his own struggle to pay off college debt and taking another dig at his likely White House rival's wealth, President Barack Obama sought on Tuesday to expand his advantage with young voters with a call to make education more affordable.
In a speech about rising education costs, a key theme of his re-election campaign, Obama said he knew firsthand how paying for university could hurt families and ding the economy.
"I didn't just read about this. I didn't just get some talking points about this. I didn't just get a policy briefing on this. Michelle and I, we've been in your shoes," the Democrat told students at the University of North Carolina at Chapel Hill.
"We didn't come from wealthy families. So when we graduated from college and grad school, we had a mountain of debt. When we got married, we got poorer together," he said, noting they only finished paying off their student loans about eight years ago.
Though Obama has talked about his modest background and his student loans before, his emphasis on wealth seemed designed as a swipe at Republican presidential hopeful Mitt Romney, the multimillionaire son of a former auto executive and Michigan governor.
The Obamas attended some of the most expensive universities in the United States. The president went to Columbia University and Harvard Law School, and the first lady went to Princeton University and Harvard Law School. Romney also attended Harvard for law school and a graduate degree in business.
Obama's two-day trip, which includes stops in Iowa and Colorado - both states he hopes to win on Nov. 6 - centers on his effort to get Congress to extend low interest rates on college loans to more than 7.4 million students.
If lawmakers fail to act, rates on the loans will double on July 1 to 6.8 percent - this at a time when other loans boast near record low rates. Obama called on Congress to act to prevent that from happening.
Romney, the former governor of Massachusetts, also urged Congress to act, while fitting in a dig at the Democrat as well.
"President Obama's failed leadership on the economy has led to the weakest recovery since the Great Depression, where 50 percent of recent college graduates are unemployed or underemployed," he told reporters on Monday.
"Given the bleak job prospects that young Americans coming out of college face today, I encourage Congress to temporarily extend the current low rate on subsidized undergraduate Stafford loans. I also hope the president and Congress can pass the extension responsibly, that offsets its cost in a way that doesn't harm the job prospects of young Americans."
The back and forth comes as a new study shows Obama is gaining ground with young voters, who helped propel him to the presidency in 2008.
The White House says roughly 160,000 students in North Carolina will rack up some $1,000 in additional debt without congressional action. In Colorado, 167,000 students would suffer, while 7.4 million students nationwide would be affected.
Obama's re-election campaign dismissed Romney's support for congressional action, saying the former Massachusetts governor supported a Republican budget proposal that would result in higher student loan rates and fewer education grants.
Republicans insist that Democrats created the problem in the first place when they controlled Congress and passed a bill that cut rates on subsidized Stafford loans in 2007 but allowed them to revert back to higher levels after four years.
And a spokesman for Republican Speaker of the House of Representatives John Boehner said federal student loan rates would also double in 2013 under Obama's budget. (Editing by Jackie Frank)