Washington(CNN) The Department of Homeland Security is running out of space at its detention facilities for families and unaccompanied children crossing over the US-Mexico border, Secretary Kirstjen Nielsen said in an interview with CNN Friday.
"We've had a huge increase in families. ...What that means for us -- our facilities are out of space," Nielsen said.
"[F]irst and foremost, it's just a lack of facilities," she said. "We're out of space unfortunately given all of the increase in numbers."
Nielsen's comments come as the Trump administration is pushing to change regulations so it can detain families longer and arguing it needs funding for more detention space.
There were about 12,774 people arrested with at least one other family member at the Southwest border in August, a nearly 40% increase over the previous month, according to US Customs and Border Protection.
Manuel Padilla, chief of the CBP's Rio Grande Valley sector, told reporters the numbers are expected to continue to rise.
"The situation is going to continue to grow, and at the end of the day it's going to require congressional action to close the immigration loopholes," said Padilla.
Padilla said that fiscal year 2018 was a "record year" of families crossing the US-Mexico border in the Rio Grande Valley region.
The end-of-fiscal-year numbers have not yet been released by Customs and Border Protection, but Padilla's assessment indicates that the numbers will show an all-time high for family apprehensions across the Southwest border, as more than 50% of all family apprehensions took place in the Rio Grande Valley this year. Apprehensions are used as a measure of unauthorized border crossings.
"This is the highest we've ever seen before," Padilla told CNN at the Conference on Prosperity and Security in Central America in Washington.
Both Nielsen and Padilla called on Congress to reform the immigration system and fix the policies they argue are contributing to the mass migration of families.
"If we do not close the immigration loopholes that currently exist, this population will continue to grow exponentially," Padilla said.
Because of the increase in families crossing the border, the Department of Homeland Security has been screening specifically for fraudulent cases, according to Padilla.
Padilla said there were "well over 900 cases" of fraud in fiscal year 2018 in the Rio Grande Valley.
"We see a lot of parents with children that not necessary belong to them or we see people that are over 17 years of age and with fraudulent birth certificates that try to come in as a minor," Padilla said.
In 2014, there was an influx of children crossing the border from Central America, with roughly 1,200 or so crossing the Rio Grande every day. The federal government was forced to open additional facilities after holding centers in Texas could no longer accommodate the large numbers of children and mothers traveling alone with their kids.
"The big difference now is we're a lot better prepared," Padilla said. "We have the infrastructure, we have the contracts, we have the interagency agreements to better deal with this traffic. However with the increases that we are seeing, the population exponentially growing is really hindering the border security mission, because you have to dedicate so many resources for this population."