The National Republican Senatorial Committee has posted its best fundraising month of the midterm election cycle so far, the committee confirmed Tuesday.

Sen. Rob Portman, the NRSC vice chair for finance, announced at a weekly lunch among Republican senators that the committee raised nearly $6.4 million in March, finishing the month with nearly $15.9 million on hand.

"Another record month shows that we are building momentum and that Republicans across the country are highly energized," Portman said later in a statement. "Thanks to the strong financial support of thousands of people and my GOP colleagues, great candidates across the map and an optimistic agenda, Republicans are one step closer to bringing back the Senate this fall, but there is still work to be done."

The Democratic Senatorial Campaign Committee, meanwhile, has not yet announced its fundraising totals for March, but the committee will likely see a notable boost from several fundraising events with President Obama last month. In February, the DSCC brought in $6.8 million without any fundraisers featuring the president.

Both party committees will need all of the fundraising might they can muster in this competitive midterm election cycle, when Republicans are hopeful they will net six seats to win a majority in the Senate. The number of competitive races has ballooned in recent weeks to include Colorado and New Hampshire, which will likely spread money even thinner than previously planned.