(CNN) - The super PAC supporting President Barack Obama's re-election reported raising just under $1.6 million in April, well below the amount raised by the group supporting Obama's rival Mitt Romney.
Priorities USA Action also reported having $4.7 million cash on hand at the end of April, slightly more than half of the amount in Restore Our Future's war chest. Restore Our Future is supporting Romney's bid for the White House. Both groups recently filed April fund-raising numbers with the Federal Election Commission.
Labor groups donated big to the pro-Obama group in April. The largest contribution came from the National Air Traffic Controllers Association, which gave the organization $1 million. Other groups putting money into Priorities included the United Association of Journeymen and Apprentices, a group affiliated with the plumbing industry, and the National Association of Social Workers.
In total, Priorities spent about $1.9 million in April, about a million dollars less than Restore Our Future spent last month.
In February, the president's re-election campaign announced it would urge donors to contribute to Priorities USA. The move represented a reversal of Obama's position on the third-party spending giants, which were made increasingly possible by the 2010 U.S. Supreme Court ruling on the Citizens United case.
– CNN's Ashley Killough contributed to this report.