Sen. Marco Rubio's prominent but unpopular push for immigration reform did not dampen his second quarter fundraising. In fact, the Florida Republican's latest campaign finance report will show an increase over his first-quarter take, according to sources familiar with the senator's Federal Election Commission filing.

Rubio raised more than $3 million between April and June for the Rubio Victory Committee, a national fundraising operation that feeds his leadership PAC and personal campaign account. The take bested Rubio's first quarter fundraising by 31 percent, with over half of the money coming from grassroot contributors in donations of less than $200 each.

The senator, a potential 2016 presidential candidate, reported a combined total of nearly $3 million in cash-on-hand in his political committees, including $980,000 in the Reclaim America Political Action Committee and $1.97 million in his Senate re-election committee. Rubio raised $5.28 million during the first six months of 2013.

Rubio recently told the Washington Examiner that he would decide in 2014 whether to run for re-election to the Senate in 2016, seek the White House, or pursue some other opportunity.