GOP Sens. John Barrasso, John Cornyn, Ted Cruz and Pete Ricketts railed against the Biden administration's border policies as migrants continue to enter the U.S. illegally. 

"We have just returned from our southern border, and it is painfully clear that with Joe Biden's open border policy, our country is really at an increased threat for a terrorist attack," said Barrasso, the Senate Republican Conference chairman, during a press conference Tuesday.

Border Patrol agents seized immigrants carrying with them explosive devices "tailored for terrorism," he said. 

Following the border trip last Thursday and Friday, Ricketts added that the country is "opening ourselves up for a terrorist attack."

BORDER PATROL AGENTS RELEASED OVER 900,000 ILLEGAL IMMIGRANTS INTO THE US LAST FISCAL YEAR

John Barrasso, John Thune, Steve Daines

Sen. John Barrasso (R-WY) speaks after a Republican policy luncheon at the U.S. Capitol on March 28, 2023 in Washington, D.C. (Kevin Dietsch/Getty Images)

Cruz, who has led several groups of lawmakers to southwest Texas, said Border Patrol agents are "frustrated" because "they risk their lives catching dangerous people, and they turn around and their political superiors just let them go."

"And the next day, they go back and catch the same people all over again," he said.

Minors are often accompanied by older men, and it is unclear whether they are actually related to the child, Cruz said. 

"We know under the Trump administration when they DNA tested grown men with children about 30% of them were not related to the kids. That's because you get preferential treatment if you arrive as a family unit," Cruz said.

WHITE HOUSE FUNDING REQUEST INCLUDES $14 BILLION FOR BORDER AS CRISIS HITS NEW RECORDS

Republican Texas Sen. Ted Cruz

Sen. Ted Cruz, R-Texas, stands alongside his fellow Republican senators at a press conference addressing the national debt on Wednesday, Jan. 25, 2023. (Fox Business)

Meanwhile, Department of Homeland Security Alejandro Mayorkas confirmed there were more than 600,000 known gotaways at the border in fiscal year 2023 during a hearing in the Senate Homeland Committee Tuesday morning.

The Biden administration recently called on Congress to provide an additional $14 billion in funding for border operations, including for processing, support for states and communities into which migrants have been released, and additional agents.

The White House says the money includes funding for transportation, including removal flights and resources for alternatives to detention. It also includes money for "non-custodial housing options" for those in expedited removal, including facilities with housing, legal services and medical care.

However, Republican lawmakers contend Biden's request will only speed up asylum processing without fixing the problem of flowing migrants by restoring Title 42, a COVID-19-era provision that allowed for faster expulsion of illegal entrants. 

"What the Border Patrol tells us… is there's no consequences associated with illegal entry in the United States," Cornyn said. "And these criminal organizations that smuggle people and drugs are smart. They know how to exploit our system."

Barrasso said the Biden administration's goal with the supplemental funding is to provide "money to make people come in easier."

HIGH MIGRANT NUMBERS BREAK MULTIPLE RECORDS IN NEW BLOW TO BIDEN BORDER STRATEGY 

John Cornyn

Sen. John Cornyn (R-TX) delivers his opening statement during a Senate Judiciary Committee hearing entitled "Law Enforcement Officer Safety: Protecting Those Who Protect and Serve" on July 26, 2022 at the U.S. Capitol in Washington, D.C. (Anna Rose Layden/Getty Images)

CLICK HERE TO GET THE FOX NEWS APP 

Border Patrol released over 900,000 illegal immigrants into the interior of the United States in fiscal year 2023, including more than 150,000 in September alone, according to data on the Customs and Border Protection website. 

The figure does not include any ICE releases or migrants encountered at ports of entry. Those released were primarily given a NTA/OR (notice to appear on own recognizance), meaning they were released into the U.S. with instructions to appear in court, often at a date years in the future. A minority were released under humanitarian parole between October 2022 and January 2023. 

As Congress gears up to negotiate a supplemental funding package, GOP lawmakers — including Sen. Minority Leader Mitch McConnell, R-Ky. — are urging for a "number of changes" that ensure tighter border security. 

"It's pretty clear that the supplemental that was set up is just a starting place," McConnell told reporters following the leadership conference's weekly luncheon last week. "We're going to go over it with a fine tooth comb, as you can see is a lot of passion among our members without having a credible border security provision in there, and we're going to make other changes as well."

Fox News' Adam Shaw and Bill Melugin contributed to this report.