Some Texas Republicans are demanding a halt on all immigration into the country after authorities named a naturalized U.S. citizen as the suspected gunman who killed two people and wounded 14 others in downtown Austin early Sunday.

More than 70 Texas House Republicans on Monday signed a letter to congressional leaders that pushes for an immediate pause on immigration until “proper vetting protocols” are put in place, joining the chorus of Republicans at all levels blaming immigration for the attack.

“The American people — and the people of Texas — demand immigration policies that place the safety and welfare of Americans first,” said the letter. State Rep. Cole Hefner, chair of the House’s Homeland Security, Public Safety & Veterans' Affairs and lead signatory, said the letter was a team effort from Texas House Republicans.

The proposed immigration freeze also specifically goes after H-1B visas, which are non-immigrant visas that allow U.S. employers to sponsor foreign workers in specialty occupations. The visas have recently been targeted by state leaders: Gov. Greg Abbott ordered all public universities and state agencies to freeze new H-1B visa applications earlier this year. The proposal would also escalate the ongoing legal immigration crackdown under the Trump administration.

The letter also called for the Department of Homeland Security to be fully funded — a demand echoed by state leaders like Lt. Gov. Dan Patrick.

“Democrats must vote to fund DHS right away to help clean up the problems their policies created,” Patrick said in a Monday post on X.

Over the past few weeks, DHS has been under a shutdown after U.S. Senate Democrats refused to vote for a funding package for the agency without changes to how immigration enforcement is conducted. The standoff came after the fatal shootings of at least three American citizens in Texas and Minnesota by federal immigration agents under the second Trump administration.

Texas Democrats, meanwhile, have responded to the Austin shooting by denouncing gun violence.

“Gun violence continues to steal the lives of too many Texans,” said a joint statement by lawmakers representing the Austin area. “Our hearts are with the victims of today’s shooting and their families. We will never stop fighting for them.”

Shortly before 2 a.m. Sunday, police say 53-year-old Ndiaga Diagne fatally shot two people and injured 14 others in downtown Austin while wearing a sweatshirt with “Property of Allah” across the front and a shirt with an Iranian flag design. The shooting happened amid the escalating conflict between the U.S. and Iran. Police then quickly responded and fatally shot Diagne at the scene.

Law enforcement authorities are investigating the shooting as a “potential act of terrorism,” but they are still working to determine the suspected gunman’s motive.

Republicans have hammered on Diagne’s immigrant background and suggested that he wasn’t properly vetted.

According to DHS, Diagne entered the United States on a tourist visa in 2000, became a lawful permanent resident by marrying a U.S. citizen in 2006 and was naturalized in 2013.

Denise Gilman, director of the Immigration Clinic at the University of Texas at Austin, said the naturalization process has long required extensive vetting. She also said studies have shown that immigrants are less likely to commit crimes than those born in the United States.

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This article first appeared on The Texas Tribune.