Story highlights Mitt Romney said lowered rates for federal student loans should be extended

President Obama is set to focus on student loan rates this week

Joined by Sen. Marco Rubio, Romney said his VP selection process is "just beginning"

Rep. Ron Paul said he will stay in the GOP nomination race even if Romney clinches

A day before President Obama is set to make a series of appearances on federal student loan rates, presumptive Republican presidential nominee Mitt Romney said Monday that he supports extending lowered rates on a popular federal student loan program for low- and middle-income undergraduates.

"With the number of college graduates who can't find work or who can only find work well beneath their skill level, I fully support the effort to extend the low interest rate on student loans," Romney said before a campaign event in Astor, Pennsylvania. Asked late last year about the rising cost of higher education, Romney suggested then that market forces would lead some colleges to lower the price of receiving an education in order to compete in attracting cost-conscious students.

Romney's announcement is the latest salvo in a fierce battle that is developing for the youth vote, a bloc Obama is focusing on this week.

JUST WATCHED Romney begins vetting VP candidates Replay More Videos ... MUST WATCH Romney begins vetting VP candidates 01:09

JUST WATCHED Romney attacks Obama on energy, unions Replay More Videos ... MUST WATCH Romney attacks Obama on energy, unions 01:29

Obama will visit the University of North Carolina, the University of Colorado and the University of Iowa on Tuesday and Wednesday. The three universities are in states Obama narrowly won in the 2008 election, which are considered battleground states again in 2012, meaning they are expected to be heavily contested by both parties in the general election. Obama will also appear on Jimmy Fallon's late night talk show Tuesday to pitch extending the lowered rates.

Five years ago, rates for the popular student loan program were lowered to 3.4% from 6.8%. Without an extension, the lowered rates are set to expire on July 1 and return to 6.8%.

Amid constant speculation about who his vice presidential pick will be, Romney was joined on the campaign trail Monday by Florida GOP Sen. Marco Rubio, a popular figure with the tea party movement.

The vice presidential selection process is "just beginning," Romney said as he stood shoulder-to-shoulder with Rubio, a conservative lawmaker of Cuban descent who hails from a battleground state.

Romney also said he was "taking a look" at Rubio's recent proposal for a conservative alternative to the DREAM Act, legislation that would grant citizenship to the children of undocumented immigrants who have been brought to the United States illegally as children.

In a cable television appearance Monday, Rep. Ron Paul, R-Texas, said he will not step aside even if Romney clinches the GOP nomination by garnering the required 1,144 delegates to the GOP convention.

"If tomorrow, Romney had the absolute number, I would probably continue in a modified way to maximize the number of delegates to go to the convention," Paul said on CNBC's "Squawk Box," adding that his supporters insist he stay in the race.

Paul, who's making his third bid for president, has failed to win a single contest this cycle and trails in the delegate race with 72 delegates to Romney's 685, according to CNN estimates. Newt Gingrich, meanwhile, has 138 delegates.

In his quest for more delgates, the longtime congressman has been campaigning in states that hold contests Tuesday, especially Rhode Island and Pennsylvania.

In addition to those two states, GOP primaries will be held Tuesday in New York, Connecticut and Delaware. The contests will be the first in the GOP presidential race since former Sen. Rick Santorum ended his presidential bid in the face of long odds, slowing fundraising and another bout of illness for his youngest child, who has a chromosomal disorder.

Romney will watch the Tuesday night's results from New Hampshire, where he scored the first political victory of his 2012 Oval Office bid.

A campaign aide said the Granite State is "where the campaign kicked off, and we see this Tuesday as when the general (election) will kick off -- so we are going back to where it all started."