Six Republicans in races across the country have accepted donations from a group that advocates for immigrants say has ties to anti-immigrant hate groups.

The candidates, running for the House, the Senate and a governor’s seat, received money from the U.S. Immigration Reform PAC this cycle, according to records filed with the Federal Election Commission.

The PAC is linked to John Tanton, a leader of the anti-immigration movement and founder of several organizations that have sought to drastically decrease legal immigration and that oppose so-called amnesty legislation for immigrants in the country illegally, and bilingual education as well.

Tanton’s wife, Mary Lou Tanton, is listed as the committee’s founder and president on the couple’s website. The pair has donated more than $6,000 to the committee since 2007, according to FEC filings.

The six candidates who have each received $500 to $2,000 from the PAC since July include Reps. Dave Brat of Virginia, Mo Brooks of Alabama and Steve King of Iowa, who are all running for re-election to the House; Rep. Lou Barletta of Pennsylvania and John James, a businessman and military veteran from Michigan, who are both running for the Senate; and Kris Kobach, the secretary of state in Kansas who is running for governor.

One day before the 2018 midterms, polls show Kobach, King and Brat in tight races. The Cook Political Report considers King a slight favorite to win, while the Kobach and Brat races are considered toss-ups.

The Southern Poverty Law Center, a civil rights-focused organization that tracks U.S. hate groups, lists Tanton as an extremist and several of his organizations as hate groups. Heidi Beirich, director of the center’s Intelligence Project, says the committee has a long history of donating to candidates who oppose any attempt to overhaul the immigration system.

“Essentially, these are people who did not want bipartisan immigration policy,” Beirich said. “They support candidates who have those anti-immigrant views.”

In letters to colleagues in 1986 and since made public, Tanton warned of a coming “Latin onslaught.” He also asked about the differences in the education ability of Hispanics and Asians, citing a “50% drop out rate” for Hispanics compared to “excellent school records and long tradition of scholarship” for Asians.

Brooks, running for re-election in Alabama’s 6th District, claimed in 2014 that President Barack Obama and Democrats were waging a “war on whites,” and called for the deportation of 8 million workers who are in the country illegally.

King has taken numerous anti-immigration stances, introducing bills that would end birthright citizenship and saying that diversity “is not a strength.”

King was criticized last month for tweeting that the Pittsburgh synagogue shooting that left 11 people dead had been “orchestrated by nasty, desperate and dishonest fake news.” The man accused of the shooting, Rob Bowers, reportedly shouted, “All Jews must die,” before the incident.

Several corporate donors pulled their support for King after his tweet.

The King, Barletta, and Brat campaigns each received at least $1,000 in the 2014 and 2016 election cycles.

The Brat, Kobach, Brooks and James campaigns and the Tantons did not respond to requests for comment. Calls to the Barletta Senate campaign were unsuccessful.

When asked for comment, Jeff King, campaign spokesman for Steve King, cited ProEnglish, a group started by Tanton in 1993 that seeks to establish English as the official language of the United States. In an email, Jeff King stated that the group is “strong supporters of our English Language Unity Act, which can’t possibly be a racist bill” because it’s sponsored by Rep. Steve Stivers, R-Ohio, the chair of the National Republican Congressional Committee.