Sen. Marco Rubio (R-Fla.) raised about $2.3 million in the first quarter of 2013, according to aides to the senator.
The funding came from 15,000 donors across all 50 states, the aides said Monday. About half of all the money Rubio received came from small donations, the aides also said.
The funds were raised through three pro-Rubio committees: his Senate reelection campaign account, his political action committee, and a joint fundraising committee.
The fundraising numbers will add to speculation that Rubio is strongly considering running for president in 2016. He is also up for reelection that year.
Rubio, for his part, has said he has not given serious thought to running for president. Still, he is regularly mentioned as a potentially strong presidential candidate and was considered for the vice presidential spot when Mitt Romney ran for president in 2012.
Rubio has grabbed the national spotlight in recent weeks as a key member of group of senators — known as the Gang of Eight — who are working to pass bipartisan immigration reform. The group is expected to unveil its immigration reform plan on Tuesday.
The first-term senator told CNN on Sunday he hasn't thought about how his leadership on immigration reform — which is to include tighter border security measures and a path to citizenship for illegal immigrants — will impact a potential presidential campaign.
"I really haven't. I have a job," Rubio said. "My belief has been if I do my job and I do my job well, I'll have options and opportunities in the future to do things whether it's run for re-election, run for something else or give someone else a chance at public service. And that's how I view this issue."
Rubio has defended the bill from conservative critics who allege it would provide amnesty to millions of people who knowingly broke the law to enter the United States.
But Rubio said it would allow illegal immigrants to stay only after meeting a series of requirements, including having a job and paying fines, and would require them to wait years before applying for citizenship.
"This is not 'amnesty.' 'Amnesty' is the forgiveness of something. 'Amnesty' is anything that says 'do it illegally, it'll be cheaper and easier,'" Rubio said on “Fox News Sunday.”