House Democrats' campaign arm on Monday said it raised almost $17 million last month and has $34 million saved for the final weeks of the election.

The Democratic Congressional Campaign Committee also said it raised more than $7 million online from 300,000 donors. Of the $163 million the committee has raised since January of 2013, more than $50 million has come from online donors.

That has allowed the committee to spend heavily, especially in recent weeks. Of the almost $131 million the committee has spent this cycle, $37 million of that was in September.

"Heading into the homestretch we can only remain competitive if we over-perform -- and that's exactly what we're doing," said Rep. Steve Israel, the New York Democrat who chairs the DCCC. "This record-breaking month is driven by our incredible grassroots supporters who refuse to sit back and let House Republicans' special interest allies buy this election."

Democrats face tough odds for toppling the Republicans' majority in the House. Republicans hold 233 seats and Democrats have 199 in the current Congress. There are three vacancies.

Yet only a handful of races are seen as competitive. When states redrew congressional districts' borders after the 2010 Census, Republicans came out with more secure seats than did the Democrats.

Even so, the DCCC has hired 815 operatives in 42 districts. Officials also say they have registered 80,000 new voters.

The National Republican Congressional Committee has not yet released its September fundraising report but faces a Monday deadline to do so.