CHICAGO (NewsNation Now) — U.S. border officials are preparing for as many as 9,000 border arrests per day by the spring, according to two Department of Homeland Security officials, which would be significantly larger than last year’s peak and could cause a headache for the Democratic administration ahead of midterm elections.

The number is a “worst-case scenario,” said one of the officials, who requested anonymity to discuss internal planning.

The nearly unprecedented number of arrests included many repeat crossers. According to U.S. Customs and Border Protection (CBP), almost half of all adults who attempted to cross the border last year had been caught in an attempt to cross before.

CBP measures what it calls “unique crossings,” or an individual’s first attempt at that year to cross and repeated counters, which are when an individual is turned away earlier in the year and then is apprehended later attempting to cross again.

Before the pandemic, about one in eight border encounters involved a person previously encountered during the prior year. However, CBP said the repeat encounter rate jumped to more than one in three encounters, including almost half of single adult encounters since they began expelling non-citizens under Title 42, the Centers for Disease Control and Prevention public health order to limit the spread of COVID-19.

While the total number of enforcement encounters increased 82 percent between 2019 and 2021, most of those are repeat attempts. There was only a 30 percent increase in new attempts.

The Biden administration grappled with a record-breaking 1.7 million border arrests last fiscal year, which ended on Sept. 30. In July 2021 — the peak of last year’s rise — daily migrant arrests averaged about 6,500, according to government statistics.

The unprecedented number of arrests also caused backups of unaccompanied children in crowded border patrol stations and fueled Republican criticism of the Democratic president’s approach to border security.

A CBP spokesperson said the agency “stands ready to address any potential increase in migrant encounters,” while at the same time “managing a fair and orderly immigration system.”

Homeland Security Secretary Alejandro Mayorkas, Biden’s top immigration official, fielded criticism from individual border patrol agents during a visit on Wednesday to Yuma, Arizona, according to four current and former agents and an audio recording posted online by the conservative website Townhall.

Some agents have grown frustrated with Biden’s approach to enforcement and say it has hurt morale.

In a statement, DHS spokesperson Marsha Espinosa said that Mayorkas “welcomes candor during these conversations, and appreciates and respects the opinions of each member of the CBP workforce.”