A California-based group is challenging the Roman Catholic Diocese of Maine's participation in an anti-gay marriage referendum, the AP reported.

The Empowering Spirits Foundation says it has filed an Internal Revenue Service complaint against the church. The group says the diocese is violating IRS nonprofit rules by collecting signatures for a political referendum.

Diocese officials vociferously lobbied lawmakers against passage of the gay marriage bill that Governor John Baldacci signed into law on May 6, making Maine the second state after Vermont to approve gay marriage legislatively, instead of by court order.

Under Maine law, voters can challenge a bill with a people's veto. To place a measure on the ballot this November requires opponents turn in 55,087 valid signatures by September 3 or 4 – at least 60 days before Election Day, but they may not begin collecting signatures until after the Legislature has adjourned.

Diocese officials, who committed early on to repeal of the gay marriage law, say IRS rules allow them to participate in the campaign and have brushed off the IRS challenge filed in a Dallas office, calling it a “bogus attempt to sidetrack the campaign.”