Amid public outrage for continuing to endorse Sen. Mark Kirk (R-Ill.) following racially charged comments about his opponent, Rep. Tammy Duckworth (D-Ill.), the Human Rights Campaign announced on Saturday it has dropped its support for the Republican in favor of his challenger.

Chad Griffin, president of the Human Rights Campaign, wrote in an open letter on Medium the board of directors for his organization’s public policy committee voted to revoke its endorsement of Kirk, marking the first-time ever the LGBT group reversed an endorsement after making it.

“Leadership is about more than the legislation one sponsors and the votes one casts,” Griffin wrote. “On Thursday night, Sen. Kirk’s comments about his opponent’s heritage were deeply offensive and racist. His attempt to use Congresswoman Tammy Duckworth’s race as a means to undermine her family’s American heritage and patriotism is beyond reproach.”

Griffin writes the Human Rights Campaign will now support Duckworth and his organization will contribute the maximum amount allowed under the law to her campaign.

Kirk made the racially charged comments during a debate with Duckworth after she talked about her family’s long history of commitment to the United States and her membership in the Daughters of the American Revolution, an organization for descendants of individuals who fought on the U.S. side in the Revolutionary War.

“I still want to be there in the Senate when the drums of war sound because people are quick to sound the drums of war and I want to be there to say this is what it costs, this is what you’re asking us to do, and if that’s case, I’ll go,” Duckworth said.

At the conclusion of Duckworth’s comments, Kirk, who has repudiated Donald Trump based on racism within his campaign, responded with his controversial and racially charged remark alluding to her Thai heritage.

“I’ve forgotten that your parents came over all the way from Thailand to serve George Washington,” Kirk said.

As NPR reported, the remark was flippant, racially charged and incorrect. Born in Thailand, Duckworth has a Thai mother of Chinese heritage and an American father who was a U.S. Marine. According to Mother Jones, Duckworth’s father, a World War II veteran, traces his heritage back to the American Revolution.

Faced with criticism for the comments, Kirk made an apology via Twitter the next day that referenced the military service of Duckworth, who lost both her legs and injured her right arm during the Iraq war.

But many said the apology wasn’t enough. The situation reignited the outrage LGBT Democrats expressed in March when the Human Rights Campaign announced it would support Kirk, who is considered the most pro-LGBT Republican in the U.S. Senate, over Duckworth.

Griffin writes in the Medium post the apology Kirk tweeted “failed to adequately address the real harm and magnitude of his words.”

“Attacking someone because of her race and ethnicity is inexcusable for anyone, but especially for a sitting U.S. senator,” Griffin said. “The diversity of our movement is our greatest strength, and Sen. Kirk’s remarks were an affront to our most fundamental values.”

The Kirk campaign couldn’t be reached by the Washington Blade over the weekend to comment over the withdrawal of the endorsement. The Duckworth campaign didn’t respond to a request to comment.

Sadie Weiner, a spokesperson for the Democratic Senatorial Campaign Committee, also commended the Human Rights Campaign reversing its alliances in the Illinois Senate race.

“This was the commonsense thing to do not only because of Mark Kirk’s offensive, racist comments, but also because of Tammy’s strong record of fighting for LGBTQ people in Illinois and across the country,” Weiner said.

Jerame Davis, director of the LGBT labor group Pride at Work, was among the advocates calling on the Human Rights Campaign to revoke its support for Kirk and said more action is needed.

“Kirk’s remarks were simply unforgivable and we’re happy to hear HRC is correcting its mistake by maxing out to Tammy Duckworth – as they should have from the start,” Davis said. “In the last days of the campaign, it will be hard to make up for the months of goodwill they built in the LGBTQ community for Kirk, but let’s hope they also spend time on the ground in Illinois campaigning for Duckworth.”