Sources at the U.S. Customs and Border Protection told Fox News on Wednesday that there have been more than 96,000 "known gotaways" at the southern border since the beginning of the fiscal year on Oct. 1. 

Agents reported seeing or detecting the migrants but were not able to take them into custody. 

The figure indicates that more than 800 individuals per day illegally crossed the border and then disappeared into the U.S. 

The numbers come after CBP sources told Fox News Digital at the start of January that migrant encounters hit a staggering 300,000 incidents in the last month of 2023. 

DEMOCRAT CUELLAR WARNS BIDEN: BORDER CRISIS WILL ‘ABSOLUTELY’ BE ELECTION ISSUE IN 2024 

Between Dec. 1 and 31, more than 302,000 migrants were documented attempting to cross the U.S. southern border.

It is the highest total for a single month ever recorded. It is also the first time migrant encounters have exceeded 300,000. 

More than 785,000 migrant encounters have been reported since the beginning of the fiscal year on Oct. 1 – the highest first quarter total ever recorded. 

MIGRANT ENCOUNTERS AT SOUTHERN BORDER HIT RECORD IN DECEMBER, SOURCES SAY 

Rep. Henry Cuellar, D-Texas, is also warning fellow Democrats, including President Biden, to prepare for border security to be a top election issue in the 2024 cycle. 

Standing along the Rio Grande in Hidalgo, Texas, on Saturday, Cuellar told Fox News Digital the situation at the southern border will "absolutely" be on voters’ minds this year. 

He traveled to the border this weekend as part of a bipartisan congressional delegation that also included Reps. Monica De La Cruz, R-Texas, Randy Weber, R-Texas, and Foreign Affairs Committee Chairman Michael McCaul, R-Texas. 

"If they're looking at the same polls I've been looking at, the American public doesn't like what's happening," Cuellar said of fellow Democrats. 

Speaking of Biden, he said, "It’s in the president’s best interest politically to come up with a solution on border security." 

Fox News' Timothy H.J. Nerozzi and Elizabeth Elkind contributed to this report.