Senior aides to Sen. Marco Rubio tell Fox News they just had their best fundraising quarter in two years.

According to the aides, Rubio raised for his PAC and his re-election committee more than $2.3 million in the first quarter of 2013.

They also report that the campaign: 

-- Identified more than 15,000 new donors

-- Raised money from all 50 states

-- Received more than half of that money from low-dollar donors

The campaign raised more in the first quarter than they did in all of last year. Though Rubio is not up for re-election in Florida until 2016, the surge comes as the Republican senator plays a key role in negotiating immigration legislation, which is expected to be introduced Tuesday.

The average for a politician to raise in an "off-cycle" year is a few hundred thousand dollars, max.

Bret Baier is the Chief Political Anchor of Fox News Channel, and the Anchor & Executive Editor of "Special Report with Bret Baier.”  His book, "Three Days in January: Dwight Eisenhower’s Final Mission," published by William Morrow, will be released on January 10, 2017.