The right-leaning Hispanic Leadership Fund is asking lawmakers to reject what it calls “false information and outright lies about Latino immigrants” that were circulated by three groups advocating for lower immigration levels in the United States.

Mario H. Lopez, who is president of the HLF, sent letters Tuesday to Reps. Martha McSally, R-Ariz., and Bob Goodlatte, R-Va., asking them to “properly and thoroughly vet” information from the Center for Immigration Studies, NumbersUSA, and Federation of Americans for Immigration Reform.

Lopez warned the lawmakers “to fully understand the consequences of risking your name, credibility, and political prospects that come from working with them.”

According to Lopez, the “core beliefs” of the three groups “stand in fundamental hostility to the most basic and cherished conservative principles,” and are backed by forces that support population control and racial purity.

CIS's Mark Krikorian told the Washington Examiner the criticism is meant to silence debate on immigration reform and said Lopez used similar arguments in 2013, when the Senate wrote an immigration reform bill that provided a pathway to citizenship. The legislation passed the Senate but died in the House.

"This gadfly is acting as the conservative auxiliary of the Southern Poverty Law Center, attempting to blacklist those who disagree with their shared views on immigration," Krikorian, the executive director of CIS, told the Washington Examiner. "He tried the same smear tactics in 2013 when he was working to pass the Gang of Eight bill. The Center for Immigration Studies has always supported an ethnically-neutral immigration policy that admits fewer immigrants, but with a warmer welcome. Suggestions to the contrary are lies."

"Resorting to ad hominin attacks is a crude and common tactic of the Hispanic Leadership Fund – and the left in general," added Bob Dane of FAIR. "John Tanton and others who founded FAIR were motivated by advancing immigration policies that serve America’s broad national interests, and nothing but."

Lopez sent the letter to Goodlatte and McSally as lawmakers grapple with how to write legislation that would protect so-called Dreamers from deportation while improving border security in a way that stops the steady flow of illegal immigration into the United States.

Lopez said in the letter that the HLF wants “a workable legislative fix” for the Dreamers, who he said are "productive members of society" and contribute to the economy. Lopez said he believes FAIR, CIS, and NumbersUSA are “working feverishly against,” a deal to legalize the Dreamers.

The HLF letter levels a charge that the groups were created by a Michigan doctor who supported eugenics and “espoused troubling racial views that echo the white national sentiment.”

The three groups have been contacted for a reaction to the HLF letter but have not yet responded.