Democratic outside groups raised more than $25 million in the second quarter

— -- Five of the nation's largest outside political groups supporting Democrats raised more than $25 million in the second quarter, the organizations announced Friday.

The disclosure comes from four super PACs, including one formed by former aides to President Barack Obama called Priorities USA Action, and one non-profit, American Bridge 21st Century Foundation. The super PACs are required by law to reveal their donors and can promote individual candidates for public office, while the non-profit is not legally required to reveal its funding base. All told the five groups raised $25.5 million.

"Together we're ensuring that Democrats will have the resources to level the playing field and fight back against the right's attacks in order to keep the White House, maintain a majority in the Senate and take back the House," representatives from all five groups said in a joint statement.

The amount is only a fraction of the money raised by prominent conservative groups in the past. American Crossroads, a super PAC co-founded by Republican strategists Karl Rove and Ed Gillespie, raised $4.6 million in the month of May alone. Restore Our Future, which supports Mitt Romney's presidential campaign, raised about $5 million in the same month.

More details about the fundraising numbers, including the sources of the funding for the super PACs, will be released next week.

Here's the breakdown: