Arizona Attorney General Mark Brnovich is slamming what he calls a "laissez-faire" approach from the Biden administration to the risk of COVID-19 coming through the southern border via a massive migrant wave -- just as the U.S. is being hit by another surge in Del Rio.

Brnovich, in a letter to Health and Human Services Secretary Xavier Becerra, cites reports that more than 18% of families and 20% of unaccompanied minors who crossed the border tested positive for COVID-19 on leaving Border Patrol custody in recent weeks.

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Meanwhile, it cites former and current border officials who say that the agency has been hit with a surge in agents testing positive for COVID-19 as well as the escalating number of migrant apprehensions at the southwest border – which have been over 200,000 in both July and August.

The Republican attorney general, who has pushed back against President Biden’s vaccine mandate, accuses the administration of choosing to increase regulation and shrink liberties when it comes to battling COVID-19.

"Yet this same administration has been nothing short of laissez-faire in dealing with tens of thousands of migrants that are pouring across our open border and being ferried across our nation during the same world-wide pandemic," he says. "This hypocrisy is stunning and fundamentally unfair to American citizens."

Brnovich asks Becerra what HHS is doing to ensure migrants "will not come into contact with Americans while they are infected or exposed to COVID-19.

While the Biden administration has said that unaccompanied children are tested at HHS facilities when they are transferred into custody, there has been concerns about the release of migrant family units without COVID testing. Some testing and quarantining is handled by non-profits.

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The concerns comes as Border Patrol has been dealing with a surge of more than 14,000 Haitian migrants in Del Rio -- which DHS has said has resulted in the release of some migrants into the U.S interior.

Border Patrol sources working the Del Rio camp told Fox News on Thursday that there is no COVID testing of migrants at the camp unless they are displaying obvious symptoms.

Fox News’ Bill Melugin contributed to this report.