EXCLUSIVE: Rep. Andy Biggs, R-Ariz., on Wednesday urged Homeland Security Secretary Alejandro Mayorkas to call the situation at the border a "crisis" after the DHS chief requested staff volunteer to help with surging numbers.

"Given your recent plea for volunteers from throughout the Department of Homeland Security (DHS) to support Customs and Border Protection’s work at the border, I request that you publicly declare that the situation at the southern border is a crisis," Biggs said in a letter to Mayorkas, obtained by Fox News.

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Mayorkas this week urged DHS staff to join a "Volunteer Force" to help Customs and Border Protection (CBP) deal with what he conceded was an "overwhelming" number of migrants at the border, as the administration scrambles to deal with the escalating crisis.

"You have likely seen the news about the overwhelming numbers of migrants seeking access to this country along the Southwest Border," he said. "President Biden and I are committed to ensuring our Nation has a safe, orderly, and humane immigration system while continuing to balance all of the other critical DHS missions."

DHS CHIEF REQUESTS VOLUNTEERS TO HELP AT SOUTHERN BORDER AMID 'OVERWHELMING' MIGRANT SURGE

Volunteers will be used in a non-law enforcement capacity, with duties including managing property, preparing meals, doing supply runs, prescription medicine runs, housekeeping and assisting in control rooms. 

Mayorkas noted that the force had been used in 2019 during the border crisis in the spring and summer.

But Biggs contrasted that with statements made a week earlier by Mayorkas in which he denied there was a crisis at the border, saying instead it was a "challenge" as the administration sought to reverse what he described as cruel policies by the prior administration.

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"Calling the deteriorating humanitarian crisis at the border 'a challenge' instead of a 'crisis' demonstrates your Department’s unwillingness to protect our country from illegal immigration," Biggs wrote.

Biggs urged DHS to reinstate the Migrant Protection Protocols (MPP), which kept migrants in Mexico for the duration of their hearings. The program, set up under the Trump administration, has started to be rolled back by the Biden administration -- which recently started to process migrants at the border.

"The Department’s current actions allowing aliens previously placed in MPP into the United States sends a strong message to aliens that our border is open and encourages aliens to attempt to enter illegally," Biggs said.

He went on to urge Biden to rescind recent Immigration and Customs Enforcement (ICE) guidance that narrowed the categories of migrants subject to arrest and deportation, saying it would send a message that the agency will "enforce the law."

The Biden administration has been struggling to cope with a surge of migrants at the border, with numbers of child migrants tripling in recent weeks. Republicans have linked the surge to Biden’s policies, and GOP House Leader Kevin McCarthy is leading a delegation to the border next week.

Fox News' Peter Hasson contributed to this report.