A gay and lesbian rights organization accused a group pushing an amendment to ban same-sex marriage in Minnesota of violating state campaign finance laws by not disclosing donors behind a $250,000 contribution to the effort.

Human Rights Campaign (HRC) asked regulators with the state Campaign Finance and Public Disclosure Board to investigate the National Organization for Marriage (NOM).

"NOM has deliberately evaded Minnesota's public disclosure laws," HRC President Joe Solmonese said in a release, adding that it's a pattern the group has carried out across the country.

NOM said it has done nothing wrong and it accused HRC of being a "joke" organization that has cooked up lies out of desperation.

"We've complied with the campaign finance rules to a 'T,' even though we think they are unconstitutional," said NOM President Brian S. Brown. He added that none of the individual contributions to NOM being used in the campaign in Minnesota exceeded disclosure thresholds.

The sudden skirmish surfaced Wednesday as details from the first round of campaign disclosure reports became available to the public. More than $2 million has been raised by groups on both sides of the ballot campaign. The lead group opposing the ban, Minnesotans United for All Families, reported $1.2 million raised from 5,100 donors. The lead organization supporting the amendment, Minnesota for Marriage, reported $830,000 raised. The bulk of that was in large donations from groups, including NOM, which on its state disclosure filing did not name its individual donors.

The campaign finance board could not be reached late Wednesday.

The proposed amendment to the state Constitution will go before voters in November. It would define marriage as the union of a man and a woman. State law already does so, but supporters of the amendment say it is needed to prevent judges or a future Legislature from overturning the law.

Brad Schrade • 612-673-4777