A Mitt Romney state political action committee gave $10,000 to the anti-gay marriage group National Organization for Marriage (NOM).

According to documents released Friday by gay rights advocate Human Rights Campaign (HRC), the Free & Strong America PAC Alabama, a state-level PAC that has raised and distributed money on behalf of Romney, made the donation in 2008.

At the time, NOM was working to approve Proposition 8, California's gay marriage ban.

Internal documents released this week in connection with a Maine court case outline NOM's strategy to pit minority groups against supporters of gay marriage.

“Mitt Romney's funding of a hate-filled campaign designed to drive a wedge between Americans is beyond despicable,” said HRC President Joe Solmonese. “Not only has Romney signed NOM's radical marriage pledge, now we know he's one of the donors that NOM has been so desperate to keep secret all these years.”

NOM has defended its work.

“It's insulting to suggest that these African-American or Latino leaders are standing up because NOM is manipulating them,” spokeswoman Maggie Gallagher said during an appearance Friday on MSNBC. “We didn't cause or create this, and frankly if we could get together with the gay community and take the idea that it's bigoted or discriminatory to stand up for marriage off the table for black people or white people, we'd be happy to do it.”

The Romney campaign told The Washington Post that the donation was in line with the candidate's views.

“Gov. Romney believes marriage is an institution between a man and a woman and his PAC made a donation to a group supporting that view,” said campaign spokesperson Andrea Saul.

The Church of Jesus Christ of Latter-day Saints, of which Romney is a member, was a major contributor to the Proposition 8 campaign. Romney family members – his son Matt and two daughters-in-law – also donated to the campaign.

HRC said the donation could violate California disclosure laws.

(Related: Rick Santorum, Mitt Romney, Newt Gingrich called on to disavow NOM's pledge.)