WASHINGTON (AP) — Chicago Mayor Rahm Emanuel is stepping down from his role as a national co-chair of President Barack Obama’s campaign to help raise money for an independent “super” political action committee supporting Obama’s re-election.

An Obama campaign aide confirmed Wednesday that Emanuel is making the switch to Priorities USA Action. The super PAC is run with the help of former White House advisers and has spent millions of dollars on ads to help Obama.

Coordination between super PACs and the campaigns they support is prohibited by law.

Emanuel was chief of staff in Obama’s White House before he was elected mayor last year.

Priorities USA Action has raised about $25.5 million through July, but lags similar Republican-leaning groups in fundraising.

GOP groups have said they hope to raise more than $300 million by November to pay for ads assailing Obama or supporting his GOP challenger, Mitt Romney.