FIRST ON FOX: Republicans in the House and Senate are again urging the Department of Homeland Security’s Office of Inspector General to launch a "comprehensive" review of the Biden administration’s handling of the crisis at the southern border, as the already high numbers are expected to increase.

More than 100 Republicans in the two chambers had written to DHS Inspector General Joseph Cuffari in January requesting "a comprehensive review of the decisions by the Biden Administration that have led to the worst border crisis in United States history."

DOZENS OF HOUSE, SENATE REPUBLICANS CALL FOR DHS INSPECTOR GENERAL TO REVIEW BIDEN BORDER ACTIONS 

A spokerson for the DHS OIG confirmed to Fox News at that time that it had received the letter: "We take all requests from Congress seriously and review them to better inform our work, including ongoing and future work," the spokesperson said.

In the latest letter, a copy of which was obtained by Fox News Digital, the Republicans say there is precedent for the OIG taking up a probe based on a request from the minority party in Congress, including reports issues in 2017 and 2018. 

Both requests were led by Rep. Elise Stefanik, R-NY, and Sen. Rick Scott, R-Fla., The signers included 23 House Republicans and 10 senators.

As the Department’s Inspector General, you have the unique position to help improve the crisis at our southern border," they say. "We entrust you and your office to provide ‘independent oversight and promote excellence, integrity, and accountability within DHS.’"

PHOTO GALLERY: HOW THE CRISIS AT THE SOUTHERN BORDER UNFOLDED, AND SPIRALED OUT OF CONTROL

The lawmakers say they provided "ample evidence of mismanagement" at the highest levels of the department, including ignoring law in favor of policy directives. They have also alleged that the administration was warned by career professionals that the implementation of the administration’s policies would lead to a surge at the border.

"America is facing the worst border crisis in our history, and Congress has directly asked for your assistance and expertise," they write.

The letter comes as numbers have soared in recent months and are expected to rise in the summer months. There were more than 234,000 migrant encounters in April, and DHS Secretary Alejandro Mayorkas recently said that "numbers could rise further."

MEXICO, NORTHERN TRIANGLE HEADS OF STATE SKIP SUMMIT OF THE AMERICAS AS ILLEGAL BORDER CROSSINGS SOAR 

Officials had warned that ending expulsions under the Title 42 public health order, as the Biden administration had tried to do last month, could see more numbers at the border. However, a federal judge has so far blocked that attempt.

In a statement, Rep. Stefanik noted the migrant caravan heading toward the U.S. border from southern Mexico, calling it the "direct result of the failed, open-border policies of Joe Biden." 

"Since he took office, paused deportations for millions of illegal immigrants, and halted construction of the border wall, we have witnessed over 2.6 million illegal immigrants who have been emboldened by these policies apprehended at our border. Illegal immigration is fueling the flow of illegal drugs into our communities and human trafficking across our border, making all our communities less safe," she said. "It is time for Americans to know why this crisis is continuing, and I am proud to lead the push for answers. I will not allow this administration to get away with their failed policies."

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Sen. Scott said that the mismanagement of the administration had led to an "unprecedented humanitarian and national security crisis for our nation." 

"For over a year, I have demanded real action to secure the border, and back in January, I urged the Biden administration to investigate the cause of its border failures. We must get to the bottom of this and ensure accountability for this man-made crisis," he said in a statement. "We won’t stop fighting until the border is secure and the American people get the answers they deserve."