SAN ANTONIO, Texas — Border Patrol agents have been quietly releasing immigrant families apprehended at the southern border rather than transferring them to Immigration and Customs Enforcement to continue being held in federal custody, a senior Department of Homeland Security official told reporters Tuesday.

Acting ICE Director Ronald Vitiello said the situation at the U.S.-Mexico border has become so dire that Border Patrol agents are letting families go free into the United States and telling them to show up for asylum hearings in the future instead of putting them in ICE custody for 20 days, the maximum amount of time they can be detained due to a 2015 court ruling.

"CBP [Customs and Border Protection] is doing some of their own release and as the flow continues, we may have to start doing that," Vitiello said following a speech at the Border Security Expo.

Vitiello, who is still navigating the Senate confirmation process since his nomination to lead the agency last summer, said ICE is "barely keeping up" with the people it is taking from CBP, prompting border agents to take matters into their own hands.

"They are overwhelmed, and we are in a position where we’re not able to help them as fast as we want to," he said.

Vitiello, who worked for CBP for three decades, said the release an unspecified number of undocumented immigrants into the U.S. is "not really different" than what CBP did in the mid-2000s. Back then, Border Patrol agents were arresting nearly 100,000 people per month and would release some out the back door of stations.

It's not clear how many immigrant families have been released by CBP and not transferred onto ICE.

Border Patrol expects to apprehend 100,000 illegal border crossers in March, the majority of whom are families and unaccompanied children, and must be handled differently than single adults.

Vitiello said ICE is "grateful" to nongovernmental organizations, many of which are migrant advocacy groups, but said even nonprofits are in a "dire" situation as they struggle to feed, clothe, relocate, and house tens of thousands of people being released into the country each month.

He pushed back on the notion that immigration officers are "dumping" people on the streets, saying there was "nowhere to put them" after they were released from federal custody.

During the 2014 and 2015 surges of unaccompanied minors at the southwest border, ICE set up temporary facilities to hold children and families. Vitiello said there are no concrete plans to do so in this case, but did not share why.