More than 1,000 migrants wait in line to be processed by US Border Patrol agents after crossing the Rio Grande from Mexico on December 18 in Eagle Pass, Texas.
Washington CNN  — 

Federal authorities reported a seven-day average of more than 9,600 migrant encounters along the US southern border in December, according to a Homeland Security official, among the highest amounts ever recorded as the US wrestles with an unprecedented surge.

Authorities are apprehending record levels of migrants at the US southern border on a daily basis, stretching already overwhelmed resources. The seven-day average reported on November 28 was around 6,800 encounters.

Border apprehensions have been gradually increasing since the summer. Last month, border authorities apprehended about 192,000 migrants between ports of entry, a 2% increase compared with the 188,000 migrant apprehensions in October, US Border Patrol Chief Jason Owens previously told CNN.

But over recent days, more than 10,000 migrants have unlawfully crossed the US-Mexico border daily – numbers not seen since days before the lifting of a Covid-era restriction known as Title 42 that allowed authorities to turn back migrants at the border. What’s uniquely challenging about this moment is that multiple sectors – many of them remote – are overwhelmed so usual processes to try to decompress or to process migrants are more complicated and result in migrants waiting in droves to be taken into custody.

The lack of capacity and resources to address the issue is leading to the type of scenario US officials once planned for but hoped wouldn’t materialize, and some are warning that the US southern border is near a “breaking point.”

The worsening situation culminated this week in a call between US President Joe Biden and Mexican President Andrés Manuel López Obrador to place pressure on Mexico to do more to stem the flow of migrants. Both agreed more enforcement is needed, and senior US officials will travel to Mexico in the coming days.

The two spoke as the US seeks additional assistance to drive down the number of migrants arriving at the US-Mexico border. The call came at a politically delicate moment for Biden, who has repeatedly grappled with migrant surges fueled by deteriorating conditions in the Western Hemisphere.

In their call, the two presidents agreed that “additional enforcement actions are urgently needed” to reopen ports on the US-Mexico border, where the migrant surge has strained federal resources and led to port closures, National Security Council spokesman John Kirby told reporters.

In November, US Border Patrol recorded 191,113 encounters between ports of entry along the southwest border, up from October when authorities apprehended nearly 189,000 migrants, as CNN previously reported. CBP’s total encounters along the southwest border in November were 242,418. That figure includes people who went to the ports of entry.

“CBP continues to execute its important mission to protect the American people, safeguard our borders, and enhance the nation’s economic prosperity by implementing operational plans, surging personnel and decompressing areas along the southwest border while processing and vetting migrants who are encountered humanely, safely, and efficiently, consistent with our laws,” said Senior Official Performing the Duties of the Commissioner Troy A. Miller in a statement.

Under the Biden administration, the Department of Homeland Security considered multiple scenarios and planned for surges at the US southern border as high as 16,000 to 18,000 arrivals a day, ahead of the lifting of Title 42, which officials worried would prompt a surge.

“We could have — and we could sustain — a couple days at 12,000 encounters,” a former Homeland Security official told CNN.

“But the reality is that a sustained flow of 12,000 to 14,000 is what we determined would buckle the system. Anything beyond that started a significant strain of resources and detention. Ultimately, we knew we were surpassing the capabilities of DHS,” the former official said. “It will break.”

The Homeland Security official stressed that the situation at the US-Mexico border, where personnel are being moved around to try to absorb the flow of migrants and thousands of people are waiting to be processed, is nearing a “breaking point.”

The nationalities and demographics of migrants have also consistently presented a challenge for authorities because there aren’t enough detention spaces or repatriation flights for those who don’t qualify for asylum.

The surge, according to border officials, is being driven by pseudo-legitimate travel agencies and organized transportation networks that are advertising travel to the US southern border and ultimately connecting migrants to smugglers.

This week, there were more than 26,000 migrants in US Customs and Border Protection custody – nearly 10,000 people over capacity.

This story has been updated with additional reporting.