Pro-Obama super-PAC sees April fundraising fall to $1.6 million

The main super-PAC supporting President Obama's reelection saw its fundraising plummet in April to $1.6 million. 

That's down from the $2.5 million that Priorities USA raised in March, which was the high-water mark so far for the pro-Obama super-PAC. 

While the main super-PAC supporting Mitt Romney's campaign also saw its fundraising fall in April, the low haul will increase worries among Democrats that Romney will have a significant advantage over the president when it comes to super-PAC fundraising. 

Obama and the Democratic National Committee are outpacing Romney and the Republican National Committee when it comes to fundraising, but outside GOP or conservative super-PACs have the potential to even the playing field, or tilt it toward Romney. 

Obama has given the independent group an official nod of approval, but donors still do not seem to have warmed up. 

One factor to watch going forward is whether Obama's announcement earlier this month that he supports gay marriage will turn the tide at all. Many of Obama's top fundraisers are gay, and the president's stamp of approval for gay marriage could increase enthusiasm for his campaign among wealthy donors. 

The pro-Romney super-PAC Restore our Future raised $4.6 million, a low mark for the group and down from $8.7 million in March, according to financial disclosure forms filed with the Federal Election Commission.

Restore our Future spent $2.9 million supporting Romney while Priorities USA spent $1.9 million supporting the president in April, with both groups appearing to be gearing up for further fundraising efforts.

Restore Our Future had $8.2 million in cash on hand at the end of the reporting period, while Priorities USA had $4.7 million total cash on hand at the end of the month.

American Crossroads, a super-PAC backed by GOP strategist Karl Rove that opposes Obama, reported raising $1.8 million, and it has $25.5 million in the bank.

— Updated at 9:08 a.m.