The head of U.S. Customs and Border Protection (CBP) declared Wednesday a "full-blown emergency" at the southern border, as the number of apprehensions surged last month to levels not seen in more than a decade.

Responding on "America's Newsroom" Thursday, former Department of Homeland Security official Theresa Cardinal Brown said it's clear that authorities at the border are in a state of "desperation."

Brown said the situation is different from years past because of the number of families and children who are seeking asylum at the border and having to be detained.

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In his comments to reporters, Acting CBP Commissioner John Sanders called the immigration system "broken," explaining that facilities housing migrants near the border are "well beyond capacity."

"This ongoing crisis has placed a tremendous strain on our limited resources and operational effectiveness," he warned.

Brown told Bill Hemmer that Border Patrol agents and other officials feel like they're not getting enough support and resources from lawmakers in Washington, D.C.

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"I hear very much the desperation of operators and people whose job it is to deal with the people they encounter at the border effectively and humanely, who feel like they're not able to do their job. ... It is a crisis," she said.

Brown said the White House and lawmakers from both parties need to come together and figure out how to deal with the crisis.

She said tensions are high between House Democrats and President Trump in particular, but she pointed back to Bill Clinton negotiating "significant legislation while he was under impeachment."

U.S. Customs and Border Protection reported nearly 133,000 arrests in May. The number surpassed 144,000 when counting migrants deemed inadmissible -- more than a 30 percent increase from the prior month and double the influx recorded at the beginning of the year.

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The number of apprehensions was the highest monthly total in more than 13 years. In April, authorities recorded 99,304 arrests.

The latest figures could embolden President Trump amid tense negotiations with Mexico over the immigration crisis.

Last week, in an effort to force Mexico to do more to “stop the invasion” of migrants into the U.S., the president vowed to impose a new 5 percent tariff on all Mexican imports. The tariffs, set to go into effect on June 10 absent an agreement, would increase over time, reaching 25 percent by Oct. 1.

Fox News' Brooke Singman and Jake Gibson contributed to this report.