WASHINGTON — The House Republican campaign committee raised almost $10 million in March and has $31.2 million banked to defend the party’s majority, according to financial reports filed Sunday.

The National Republican Congressional Committee’s $21.2 million fundraising haul in January, February and March gave the group its best first-quarter showing since 2003. It also puts the committee roughly $8 million ahead of its fundraising at this point in 2012.

Still, the Republican committee faces a well-funded challenge from House Democrats, who amassed a $40 million fund.

Those fundraising updates – like dozens of others due by midnight Sunday – suggest that donors are starting to open their wallets for groups willing to spend hundreds of millions of dollars on federal races from coast to coast. The fundraising was fast approaching the $1 billion mark, fueled by donors on each side writing checks to committees and organizations in a show of just how politically divided the United States remains.

“This outstanding fundraising effort will enable the NRCC to stay on offense against House Democrats who continue to support Obamacare and failed leadership of (House Democratic leader) Nancy Pelosi,” committee executive director Liesl Hickey said.

The Democratic Congressional Campaign Committee raised $10.3 million in March despite deep skepticism that Republicans can lose their majority in November. Its $40 million in savings puts it atop the fundraising contest among party-directed campaign committees and outpaced most three-month fundraising tallies released thus far from super political action committees, which can accept unlimited donations. Donations to party-run campaign committees are capped at $32,400.

“The DCCC has sustained a blistering fundraising pace this election cycle because Americans are sick and tired of a Republican Congress,” Rep. Steve Israel of New York, who leads the Democrats’ House campaign arm, said last week.

Republicans outnumber Democrats by 34 seats in the 435-member House and there are three vacancies. Democrats face a steep climb to reclaim control for the first time since tea party-aligned candidates helped put the Republicans back in power after the 2010 elections.

Democrats also had an advantage with their Senate committee. The Democratic Senatorial Campaign Committee reported raising $8.1 million in March and saved $22 million. The National Republican Senatorial Committee reported raising almost $6.4 million in March and saving $15.9 million. Republicans need to pick up six seats in win the majority in the Senate.